Listen and write the missing letter.

She went by the name of Belisa Crepusculario, not because she had been baptized with that name or given it by her mother, but because she herself had searched until she found the poetry of "beauty" and "twilight" and cloaked herself in it. She made her living selling words. She journeyed through the country from the high cold mountains to the burning coasts, stopping at fairs and in markets where she set up four poles covered by a canvas awning under which she took refuge from the sun and rain to minister to her customers. She did not have to peddle her merchandise because from having wandered far and near, everyone knew who she was. Some people waited for her from one year to the next, and when she appeared in the village with her bundle beneath her arm, they would form a line in front of her stall. Her prices were fair. For five centavos she delivered verses from memory, for seven she improved the quality of dreams, for nine she wrote love letters, for twelve she invented insults for irreconcilable enemies. She also sold stories, not fantasies but long, true stories she recited at one telling, never skipping a word. This is how she carried news from one town to another. People paid her to add a line or two: our son was born, so-and-so died, our children got married, the crops burned in the field. Wherever she went a small crowd gathered around to listen as she began to speak, and that was how they learned about each others' doings, about distant relatives, about what was going on in the civil war. To anyone who paid her fifty centavos in trade, she gave the gift of a secret word to drive away melancholy. It was not the same word for everyone, naturally, because that would have been collective dece it. Each person received his or her own word, with the assurance that no one else would use it that way in this universe or the Beyond. Belisa Crepusculario had been born into a family so poor they did not even have names to give their children. She came into the world and grew up in an inhospitable land where some years the rains became avalanches of water that bore everything away before them and others when not a drop fell from the sky and the sun swelled to fill the horizon and the world became a desert. Until she was twelve, Belisa had no occupation or virtue other than having withstood hunger and the exhaustion of centuries. During one interminable drought, it fell to her to bury four younger brothers and sisters, when she realized that her turn was next, she decided to set out across the 2 plains in the direction of the sea, in hopes that she might trick death along the way. The land was eroded, split with deep cracks, strewn with rocks, fossils of trees and thorny bushes, and skeletons of animals bleached by the sun. From time to time she ran into families who, like her, were heading south, following the mirage of water. Some had begun the march carrying their belongings on their back or in small carts, but they could barely move their own bones, and after a while they had to abandon their possessions. They dragged themselves along painfully, their skin turned to lizard hide and their eyes burned by the reverberating glare. Belisa greeted them with a wave as she passed, but she did not stop, because she had no strength to waste in acts of compassion. Many people fell by the wayside, but she was so stubborn that she survived to cross through that hell and at long last reach the first trickles of water, fine, almost invisible threads that fed spindly vegetation and farther down widened into small streams and marshes. Belisa Crepusculario saved her life and in the process accidentally discovered writing. In a village near the coast, the wind blew a page of newspaper at her feet. She picked up the brittle yellow paper and stood a long while looking at it, unable to determine its purpose, until curiosity overcame her shyness. She walked over to a man who was washing his horse in the muddy pool where she had quenched her thirst. "What is this?" she asked. "The sports page of the newspaper," the man replied, concealing his surprise at her ignorance. The answer astounded the girl, but she did not want to seem rude, so she merely inquired about the significance of the fly tracks scattered across the page. "Those are words, child. Here it says that Fulgencio Barba knocked out El Negro Tiznao in the third round." That was the day Belisa Crepusculario found out that words make their way in the world without a master, and that anyone with a little cleverness can appropriate them and do business with them. She made a quick assessment of her situation and concluded that aside from becoming a prostitute or working as a servant in the kitchens of the rich there were few occupations she was qualified for. It seemed to her that selling words would be an honorable alternative. From that moment on, she worked at that profession, and was never tempted by any other. At the beginning, she offered her merchandise unaware that words could be written outside of newspapers. When she learned otherwise, she calculated the infinite possibilities of her trade and with her savings paid a priest twenty pesos to teach her to read and write, with her three 3 remaining coins she bought a dictionary. She poured over it from A to Z and then threw it into the sea, because it was not her intention to defraud her customers with packaged words. One August morning several years later, Belisa Crepusculario was sitting in her tent in the middle of a plaza, surrounded by the uproar of market day, selling legal arguments to an old man who had been trying for sixteen years to get his pension. Suddenly she heard yelling and thudding hoofbeats. She looked up from her writing and saw, first, a cloud of dust, and then a band of horsemen come galloping into the plaza. They were the Colonel's men, sent under orders of El Mulato, a giant known throughout the land for the speed of his knife and his loyalty to his chief. Both the Colonel and El Mulato had spent their lives fighting in the civil war, and their names were ineradicably linked to devastation and calamity. The rebels swept into town like a stampeding herd, wrapped in noise, bathed in sweat, and leaving a hurricane of fear in their trail. Chickens took wing, dogs ran for their lives, women and children scurried out of sight, until the only living soul left in the market was Belisa Crepusculario. She had never seen El Mulato and was surprised to see him walking toward her. "I'm looking for you," he shouted, pointing his coiled whip at her, even before the words were out, two men rushed her -- knocking over her canopy and shattering her inkwell -- bound her hand and foot, and threw her like a sea bag across the rump of El Mulato's mount. Then they thundered off toward the hills. Hours later, just as Belisa Crepusculario was near death, her heart ground to sand by the pounding of the horse, they stopped, and four strong hands set her down. She tried to stand on her feet and hold her head high, but her strength failed her and she slumped to the ground, sinking into a confused dream. She awakened several hours later to the murmur of night in the camp, but before she had time to sort out the sounds, she opened her eyes and found herself staring into the impatient glare of El Mulato, kneeling beside her. "Well, woman, at last you've come to," he said. To speed her to her senses, he tipped his canteen and offered her a sip of liquor laced with gunpowder. She demanded to know the reason for such rough treatment, and El Mulato explained that the Colonel needed her services. He allowed her to splash water on her face, and then led her to the far end of the camp where the most feared man in all the land was lazing in a hammock strung between two trees. She could not see his face, because he lay in the deceptive shadow of the leaves and the indelible shadow of all his years as a bandit, but she imagined from the way his 4 gigantic aide addressed him with such humility that he must have a very menacing expression. She was surprised by the Colonel's voice, as soft and well-modulated as a professor's. "Are you the woman who sells words?" he asked. "At your service," she stammered, peering into the dark and trying to see him better. The Colonel stood up, and turned straight toward her. She saw dark skin and the eyes of a ferocious puma, and she knew immediately that she was standing before the loneliest man in the world. "I want to be President," he announced. The Colonel was weary of riding across that godforsaken land, waging useless wars and suffering defeats that no subterfuge could transform into victories. For years he had been sleeping in the open air, bitten by mosquitoes, eating iguanas and snake soup, but those minor inconveniences were not why he wanted to change his destiny. What truly troubled him was the terror he saw in people's eyes. He longed to ride into a town beneath a triumphal arch with bright flags and flowers everywhere, he wanted to be cheered, and be given newly laid eggs and freshly baked bread. Men fled at the sight of him, children trembled, and women miscarried from fright, he had had enough, and so he had decided to become President. El Mulato had suggested that they ride to the capital, gallop up to the Palace, and take over the government, the way they had taken so many other things without anyone's permission. The Colonel, however, did not want to be just another tyrant, there had been enough of those before him and, besides, if he did that, he would never win people's hearts. It was his aspiration to win the popular vote in the December elections. "To do that, I have to talk like a candidate. Can you sell me the words for a speech?" the Colonel asked Belisa Crepusculario. She had accepted many assignments, but none like this. She did not dare refuse, fearing that El Mulato would shoot her between the eyes, or worse still, that the Colonel would burst into tears. There was more to it than that, however, she felt the urge to help him because she felt a throbbing warmth beneath her skin, a powerful desire to touch that man, to fondle him, to clasp him in her arms. All night and a good part of the following day, Belisa Crepusculario searched her repertory for words adequate for a presidential speech, closely watched by El Mulato, who could not take his eyes from her firm wanderer's legs and virginal breasts. She discarded harsh, cold words, words 5 that were too flowery, words worn from abuse, words that offered improbable promises, untruthful and confusing words, until all she had left were words sure to touch the minds of men and women's intuition. Calling upon the knowledge she had purchased from the priest for twenty pesos, she wrote the speech on a sheet of paper and then signaled El Mulato to untie the rope that bound her ankles to a tree. He led her once more to the Colonel, and again she felt the throbbing anxiety that had seized her when she first saw him. She handed him the paper and waited while he looked at it, holding it gingerly between thumbs and fingertips. "What the shit does this say," he asked finally. "Don't you know how to read?" "War's what I know," he replied. She read the speech aloud. She read it three times, so her client could engrave it on his memory. When she finished, she saw the emotion in the faces of the soldiers who had gathered round to listen, and saw that the Colonel's eyes glittered with enthusiasm, convinced that with those words the presidential chair would be his. "If after they've heard it three times, the boys are still standing there with their mouths hanging open, it must mean the thing's damn good, Colonel" was El Mulato's approval. "All right, woman. How much do I owe you?" the leader asked. "One peso, Colonel." "That's not much," he said, opening the pouch he wore at his belt, heavy with proceeds from the last foray. "The peso entitles you to a bonus. I'm going to give you two secret words," said Belisa Crepusculario. "What for?" She explained that for every fifty centavos a client paid, she gave him the gift of a word for his exclusive use. The Colonel shrugged. He had no interest at all in her offer, but he did not want to be impolite to someone who had served him so well. She walked slowly to the leather stool where he was sitting, and bent down to give him her gift. The man smelled the scent of a mountain cat issuing from the woman, a fiery heat radiating from her hips, he heard the terrible whisper of her hair, and a breath of sweetmint murmured into his ear the two secret words that were his alone. "They are yours, Colonel," she said as she stepped back. "You may use them as much as you 6 please." El Mulato accompanied Belisa to the roadside, his eyes as entreating as a stray dog's, but when he reached out to touch her, he was stopped by an avalanche of words he had never heard before; believing them to be an irrevocable curse, the flame of his desire was extinguished. During the months of September, October, and November the Colonel delivered his speech so many times that had it not been crafted from glowing and durable words it would have turned to ash as he spoke. He travelled up and down and across the country, riding into cities with a triumphal air, stopping in even the most forgotten villages where only the dump heap betrayed a human presence, to convince his fellow citizens to vote for him. While he spoke from a platform erected in the middle of the plaza, El Mulato and his men handed out sweets and painted his name on all the walls in gold frost. No one paid the least attention to those advertising ploys; they were dazzled by the clarity of the Colonel's proposals and the poetic lucidity of his arguments, infected by his powerful wish to right the wrongs of history, happy for the first time in their lives. When the Candidate had finished his speech, his soldiers would fire their pistols into the air and set off firecrackers, and when finally they rode off, they left behind a wake of hope that lingered for days on the air, like the splendid memory of a comet's tail. Soon the Colonel was the favorite. No one had ever witnessed such a phenomenon: a man who surfaced from the civil war, covered with scars and speaking like a professor, a man whose fame spread to every corner of the land and captured the nation's heart. The press focused their attention on him. Newspapermen came from far away to interview him and repeat his phrases, and the number of his followers and enemies continued to grow. "We're doing great, Colonel," said El Mulato, after twelve successful weeks of campaigning. But the Candidate did not hear. He was repeating his secret words, as he did more and more obsessively. He said them when he was mellow with nostalgia; he murmured them in his sleep; he carried them with him on horseback; he thought them before delivering his famous speech; and he caught himself savoring them in his leisure time. And every time he thought of those two words, he thought of Belisa Crepusculario, and his senses were inflamed with the memory of her feral scent, her fiery heat, the whisper of her hair, and her sweetmint breath in his ear, until he began to go around like a sleepwalker, and his men realized that he might die before he ever sat in the presidential chair. "What's got hold of you, Colonel," El Mulato asked so often that finally one day his chief broke 7 down and told him the source of his befuddlement: those two words that were buried like two daggers in his gut. "Tell me what they are and maybe they'll lose their magic," his faithful aide suggested. "I can't tell them, they're for me alone," the Colonel replied. Saddened by watching his chief decline like a man with a death sentence on his head, El Mulato slung his rifle over his shoulder and set out to find Belisa Crepusculario. He followed her trail through all that vast country, until he found her in a village in the far south, sitting under her tent reciting her rosary of news. He planted himself, spraddle-legged, before her, weapon in hand. "You! You're coming with me," he ordered. She had been waiting. She picked up her inkwell, folded the canvas of her small stall, arranged her shawl around her shoulders, and without a word took her place behind El Mulato's saddle. They did not exchange so much as a word in all the trip; El Mulato's desire for her had turned into rage, and only his fear of her tongue prevented his cutting her to shreds with his whip. Nor was he inclined to tell her that the Colonel was in a fog, and that a spell whispered into his ear had done what years of battle had not been able to do. Three days later they arrived at the encampment, and immediately, in view of all the troops, El Mulato led his prisoner before the Candidate. "I brought this witch here so you can give her back her words, Colonel," El Mulato said, pointing the barrel of his rifle at the woman's head. "And then she can give you back your manhood." The Colonel and Belisa Crepusculario stared at each other, measuring one another from a distance. The men knew then that their leader would never undo the witchcraft of those accursed words, because the whole world could see the voracious-puma eyes soften as the woman walked to him and took his hand in hers. Copyright © 1989 by Isabel Allende From The Stories of Eva Luna, Translated by Margaret Sayers Peden

To understand melody in music, think about some music you’re familiar with. If you were asked to hum it, what would that sound like? The part of the music that you’d hum is the melody. It’s the main thread of sound that your brain tracks and holds onto when you’re listening to music. In vocal music, the melody is sung by the lead singer. Other vocalists can provide harmony and instruments can add accompaniment, but the melody is the star of the show.What are the characteristics of melody in music? How do you describe a melody in music? A melody needs to have two things. The first is a sequence of notes, or pitches, which range from high to low. The second is rhythm, which is the timing and duration of each note. These two simple elements can create an incredible variety of combinations. Even though a melody only consists of one note at a time, it can convey so much energy and emotion. Melodies can be fast and sparkly, like “The Flight of the Bumblebee.” They can be slow and majestic, like “Finlandia.” They might be sweeping and graceful, like a Strauss waltz. Or they can be fun and exciting, like your favorite pop tunes that you love to sing along with. Melodies often tell you a lot about where a piece of music comes from. It’s easy to recognize and identify melodies from different folk traditions such as the Japanese folk song “Sakura” or the Irish tune “Star of the County Down.” Learn how to play your favorite melodies on piano, and more! Sign up now. What is melody in music? Here are some examples. Here is the famous melody for the song “Lean on Me” written out on a staff. Notice the way that the notes move up, down, and then repeat. What is melody in music? Example of Lean On Me notes on treble staff. A melody all by itself is great, but music can be even more fun when there’s an accompaniment. Here are a few bars of “Lean on Me” with the accompaniment written out. As you listen to this song, notice how the accompaniment has a very similar rhythm and movement to the melody. Then there’s that one note in the bass line that comes along every measure with its own rhythm, which adds some extra energy and movement to the song. What makes a good melody? When you create a melody, there are four types of movement you can use: Repeat (same note) Step (up or down) Skip (up or down) Leap (up or down) Stepping and repeating are the most common types of melodic motion, and this makes a melody easier to sing. Most “hummable” tunes use steps and repeats almost exclusively. This kind of melody is called conjunct. Beethoven’s “Ode to Joy,” one of the most famous melodies of all time.Skips and leaps are generally more sparing in melodies, but when thoughtfully placed they can have a powerful emotional impact. Tunes with a lot of leaps are called disjunct. Listen to Sarah Brightman sing All I Ask of You from The Phantom of the Opera starting at 0:39. This is a very disjunct melody, and challenging to sing. Great melodies also incorporate patterns that blend unity, repetition, and contrast. Our ears love patterns, but they also love novelty and growth. A good melody incorporates all of these elements. For example, listen to John William’s “Princess Leia Theme.” Can you hear the repeated pattern in the melody that gradually moves higher as the theme progresses? Now listen to the way it changes and develops into something that fits with what came before but sounds new at the same time. This is some great melodic writing! Can melody exist without rhythm? There is no way for a melody to exist without rhythm. Even if your melody only has one note, that note has a duration, and that’s the rhythm. If your melody has two notes, how long those notes last and how much time passes between hearing them is also a rhythm. A melody in music can often be recognized even when it’s performed with different rhythms. This frequently happens in live performances of pop, rock, and jazz, in which singers typically improvise slight rhythmic differences with each performance. No two renditions are exactly the same, and this constant reinterpretation keeps the music fresh. How to make a melody for a song on piano Creating your own melodies on the piano is easy and fun! There are so many ways you can discover a melody all your own. Here are a few ideas. Get some inspiration from the world around you. What can you hear right now? A clock ticking? A bird song? A car passing by your house? See if you can find some notes on the piano that imitate the sounds you hear. Think of a feeling you’d like to put into a melody. What are some ways you could make a string of notes sound happy, sad, angry, or maybe just thoughtful. Choose a line from a poem you like, or write your own. Read it out loud and put some feeling into it. Did your voice rise and fall in pitch as you were reading? Now go to the piano, start on any note you like, and try to imitate what happened when you read. Go up when your voice naturally went up, go down when your voice naturally went down. How did that sound? Now you have the perfect melody to go with those words. Too many keys on the piano? The truth is, most melodies use only a limited number of different notes. Try creating a melody using only the black keys. These form what’s called a pentatonic scale. It’s used in a lot of folk music traditions around the world and can be a great place to start if you want to create your own melodies. Remember, when you create your melody, keep it simple. Use repeated notes and steps, but add a few skips to keep things interesting. One tip about leaps: when you do put in a big leap, try doubling back and filling in the empty space you leaped over. This keeps the melody self-contained and easier to sing. Also, see if you can use the same patterns of notes and rhythms to give the melody unity, but also change those patterns to give it variety. There is no right or wrong way to create your own music. Keep trying combinations of notes and rhythms until you find something that you like. How many bars and notes are in a melody? Many types of music tend to have a prescribed number of bars, or measures. This will vary widely between different genres, and creates an overall sense of musical structure. If you’re writing a pop song, a verse will usually have between eight and sixteen bars. The prechorus that follows often has just four bars, and this “foreshortening” creates a sense of acceleration, driving the listener toward the chorus. The number of notes can also vary widely. A melody in music needs at least two notes, and a long and complex one can have hundreds or even thousands of notes. What is a countermelody in music? How many melodies should a song have? A counter melody is a melodic line that interacts with the primary melody as an independent but supportive voice. A great example of this is the song “We Don’t Talk about Bruno.” Each character sings their own melody during the piece, but these melodies all combine at the end as countermelodies. This produces a musical texture known as counterpoint. The same thing happens in “One Day More” from Les Miserables. The different melodies are first sung separately, but end up being combined in a splendid, complex texture that leads the music to its thrilling conclusion. The difference between a countermelody and regular harmony is that harmony usually supports the rhythms of the melody. A countermelody will move more independently, with different rhythms from those of the melody, and will often sound “melodic” when sung or played all by itself. A melodic song should have one main melody. This is the part that the lead voice sings. It’s usually in the spotlight, and will be the most memorable part of the music. Anything else is either harmony, countermelody, or accompaniment. Does all music have to have a melody? A piece of music doesn’t have to have a melody. There are many different kinds of music without melody. For example, a lot of music played on percussion instruments won’t have a melody. Listen to this example of Tahitian drumming. This is some great music, exciting and fun to listen to, but you’d have a hard time humming it. It’s music, but it doesn’t have a melody. Rap music is another style of music where there doesn’t have to be a melody. In rap, words are chanted rather than sung. The performer will raise and lower the pitch of their voice for emphasis, but it’s the rhythm of the words that creates most of the music. Music can even lack any melody, at least in some sections. Listen to the opening chords of “Duel of the Fates.” This choral passage is all about harmony, with little rhythmic variance or sense of melody. But it makes an effective contrast with the next section, which is bustling with rapid instrumental melodies. In some pieces, there are multiple melodic lines but there is no one main melody. When music is made up of equally important countermelodies, it creates a contrapuntal texture. Baroque composer J.S. Bach was one of the greatest masters of this style, such as in his Little Fugue in G minor. It starts with a single melodic line, the subject, but then a countermelody is added, and then more and more until several melodic lines are playing together. It’s fun to listen to, but once all the countermelodies are playing together it becomes hard to decide which part to hum along with! You’ll also hear a lot of counterpoint in jazz music, in which the different instruments are all playing together and improvising their own melodies that combine to create a rich, thick musical texture. Experience the wonder of melody in music! Whether you’re humming your favorite tune, or creating a new song all your own, melody is a memorable, shareable part of music. Enrich your music experience by being aware of, listening for, and enjoying the melodies all around you.

Ostinato Music Definition Ostinato (plural – ostinati or ostinatos) is an Italian word meaning obstinate or persistent and is used in music to describe a musical phrase or rhythm that is repeated persistently. The repeated pattern could be a melody, a figure in the bass – called a basso ostinato or simply a repeated rhythmic idea. An ostinato may be played for an entire piece of music or just during one section. The key aspect to remember in the definition of an ostinato is that it is a pattern that is repeated persistently in a piece of music. Rhythmic Ostinato A rhythmic ostinato is a rhythmic pattern that is persistently repeated. It will often be played on an untuned percussion instrument (e.g. snare drum, triangle, etc..). However, rhythmic ostinati can also be found in parts played on pitched instruments where the note pitch stays the same or where the pitches change as the phrase is repeated. The key characteristic is that it is the rhythm that is persistently repeated.In Maurice Ravel’s “Bolero” the use of a rhythmic ostinato brings a magical and almost hypnotic feel to the piece as the percussive pattern contrasts with the sweeping and almost improvisatory nature of the flute melody. Have a look at the pattern below and listen to its use in the audio extract: Rhythmic Ostinato Example from Ravel Bolero.A rhythmic ostinato is an excellent technique that composers use for creating drama and tension. One of the most famous examples of this is from “Mars” by Gustav Holst. Have a look/listen to the rhythmic pattern: Rhythmic Ostinato Example from Gustav Holst Mars. This rhythmic pattern is played relentlessly throughout the piece and forms the basis for the intense drama associated with the subject – Mars, the god of war! Have a listen to this extract of the piece performed by the United States Air Force Band:You can hear how the relentless sound of a rhythmic ostinato is extremely effective at building tension as the music around it changes and develops. This effect is heightened in the extract from Mars as the bass note remains on a G throughout the extract and acts as a pedal point. Not surprisingly, rhythmic ostinati are used widely in dramatic film music. Hans Zimmer is a film composer who makes considerable use of this technique across the many film scores he has written. Have a listen to the opening from his theme for the film “Pirates of the Caribbean” performed by the Auckland Symphony Orchestra:You can hear that there are a number of different ostinati in many of the different parts that are layered to produce the overall sound. Here is the rhythmic ostinato that forms the basis of the melody line: Rhythmic Ostinato Example Hans ZimmerMelodic ostinato A melodic ostinato is a repeated pattern where both the rhythm and the melody form the basis for the repeated pattern. These often occur in the bass part where they are called a basso ostinato. Basso Ostinato A basso ostinato is a repeated pattern in the bass part of a piece. This technique became particularly popular in the 17th century where a number of Baroque dances were based upon ostinati in the bass part. In dances such as the passacaglia the bass remained constant throughout the piece whilst the other parts developed. This technique is called “ground bass” and you can have a look at my lesson on ground bass for some examples of this. The most famous example of a basso ostinato is Pachelbel’s Canon in D. Ostinati Examples in Contemporary Music Rhythmic and melodic ostinatos have had a massive influence on contemporary popular music across a wide range of genres. This can be seen in 2 main ways: Riffs (short melodic phrases) – these are effectively contemporary expressions of ostinato. Loops – rhythmic and melodic phrases are repeated to create the characteristic sound of contemporary productions. As a result, you will probably be able to find examples of the use of repeated patterns/ostinati in most contemporary songs. However, there are some songs where the use of an ostinato provides the clear foundation for the song and these are useful examples to listen to. Examples of Ostinati Riffs Seven Nation Army by White Stripes The guitar riff from Seven Nation Army is one of the most famous modern guitar riffs and is used as an ostinato that plays throughout the song. It is an excellent example of a melodic ostinato:Back in Black by AC/DC The opening guitar riff in this song is another great example:Examples of Loops Loops are repeated patterns that are clearly built on the concept of ostinati. They are used widely in contemporary music. Hip hop songs often use loops as the foundation for the track. Still D.R.E by Dr. Dre ft. Snoop Dogg In this song a piano loop plays throughout the whole track and forms the foundation of the song:

Covalent Molecules and Compounds Just as an atom is the simplest unit that has the fundamental chemical properties of an element, a molecule is the simplest unit that has the fundamental chemical properties of a covalent compound. Some pure elements exist as covalent molecules. Hydrogen, nitrogen, oxygen, and the halogens occur naturally as the diatomic (“two atoms”) molecules H2, N2, O2, F2, Cl2, Br2, and I2 (part (a) in Figure 3.1.1). Similarly, a few pure elements exist as polyatomic (“many atoms”) molecules, such as elemental phosphorus and sulfur, which occur as P4 and S8 (part (b) in Figure 3.1.1). Each covalent compound is represented by a molecular formula, which gives the atomic symbol for each component element, in a prescribed order, accompanied by a subscript indicating the number of atoms of that element in the molecule. The subscript is written only if the number of atoms is greater than 1. For example, water, with two hydrogen atoms and one oxygen atom per molecule, is written as H2O. Similarly, carbon dioxide, which contains one carbon atom and two oxygen atoms in each molecule, is written as CO2. Covalent compounds that predominantly contain carbon and hydrogen are called organic compounds. The convention for representing the formulas of organic compounds is to write carbon first, followed by hydrogen and then any other elements in alphabetical order (e.g., CH4O is methyl alcohol, a fuel). Compounds that consist primarily of elements other than carbon and hydrogen are called inorganic compounds; they include both covalent and ionic compounds. In inorganic compounds, the component elements are listed beginning with the one farthest to the left in the periodic table, as in CO2 or SF6. Those in the same group are listed beginning with the lower element and working up, as in ClF. By convention, however, when an inorganic compound contains both hydrogen and an element from groups 13–15, hydrogen is usually listed last in the formula. Examples are ammonia (NH3) and silane (SiH4). Compounds such as water, whose compositions were established long before this convention was adopted, are always written with hydrogen first: Water is always written as H2O, not OH2. The conventions for inorganic acids, such as hydrochloric acid (HCl) and sulfuric acid (H2SO4), are described elswhere. Note! For organic compounds: write C first, then H, and then the other elements in alphabetical order. For molecular inorganic compounds: start with the element at far left in the periodic table; list elements in same group beginning with the lower element and working up. Write the molecular formula of each compound. a. The phosphorus-sulfur compound that is responsible for the ignition of so-called strike anywhere matches has 4 phosphorus atoms and 3 sulfur atoms per molecule. b. Ethyl alcohol, the alcohol of alcoholic beverages, has 1 oxygen atom, 2 carbon atoms, and 6 hydrogen atoms per molecule. c. Freon-11, once widely used in automobile air conditioners and implicated in damage to the ozone layer, has 1 carbon atom, 3 chlorine atoms, and 1 fluorine atom per molecule. Solution: a. • A The molecule has 4 phosphorus atoms and 3 sulfur atoms. Because the compound does not contain mostly carbon and hydrogen, it is inorganic. • B Phosphorus is in group 15, and sulfur is in group 16. Because phosphorus is to the left of sulfur, it is written first. • C Writing the number of each kind of atom as a right-hand subscript gives P4S3 as the molecular formula. b. • A Ethyl alcohol contains predominantly carbon and hydrogen, so it is an organic compound. • B The formula for an organic compound is written with the number of carbon atoms first, the number of hydrogen atoms next, and the other atoms in alphabetical order: CHO. • C Adding subscripts gives the molecular formula C2H6O. c. • A Freon-11 contains carbon, chlorine, and fluorine. It can be viewed as either an inorganic compound or an organic compound (in which fluorine has replaced hydrogen). The formula for Freon-11 can therefore be written using either of the two conventions. • B According to the convention for inorganic compounds, carbon is written first because it is farther left in the periodic table. Fluorine and chlorine are in the same group, so they are listed beginning with the lower element and working up: CClF. Adding subscripts gives the molecular formula CCl3F. • C We obtain the same formula for Freon-11 using the convention for organic compounds. The number of carbon atoms is written first, followed by the number of hydrogen atoms (zero) and then the other elements in alphabetical order, also giving CCl3F. Write the molecular formula for each compound. a. Nitrous oxide, also called “laughing gas,” has 2 nitrogen atoms and 1 oxygen atom per molecule. Nitrous oxide is used as a mild anesthetic for minor surgery and as the propellant in cans of whipped cream. b. Sucrose, also known as cane sugar, has 12 carbon atoms, 11 oxygen atoms, and 22 hydrogen atoms. c. Sulfur hexafluoride, a gas used to pressurize “unpressurized” tennis balls and as a coolant in nuclear reactors, has 6 fluorine atoms and 1 sulfur atom per molecule. Answer: a. N2O b. C12H22O11 c. SF6. Ionic Compounds The substances described in the preceding discussion are composed of molecules that are electrically neutral; that is, the number of positively-charged protons in the nucleus is equal to the number of negatively-charged electrons. In contrast, ions are atoms or assemblies of atoms that have a net electrical charge. Ions that contain fewer electrons than protons have a net positive charge and are called cations. Conversely, ions that contain more electrons than protons have a net negative charge and are called anions. Ionic compounds contain both cations and anions in a ratio that results in no net electrical charge. Note! Ionic compounds contain both cations and anions in a ratio that results in zero electrical charge.An ionic compound that contains only two elements, one present as a cation and one as an anion, is called a binary ionic compound. One example is MgCl2, a coagulant used in the preparation of tofu from soybeans. For binary ionic compounds, the subscripts in the empirical formula can also be obtained by crossing charges: use the absolute value of the charge on one ion as the subscript for the other ion. This method is shown schematically as follows: Crossing charges. One method for obtaining subscripts in the empirical formula is by crossing charges. When crossing charges, it is sometimes necessary to reduce the subscripts to their simplest ratio to write the empirical formula. Consider, for example, the compound formed by Mg2+ and O2−. Using the absolute values of the charges on the ions as subscripts gives the formula Mg2O2:Polyatomic Ions Polyatomic ions are groups of atoms that bear net electrical charges, although the atoms in a polyatomic ion are held together by the same covalent bonds that hold atoms together in molecules. Just as there are many more kinds of molecules than simple elements, there are many more kinds of polyatomic ions than monatomic ions. Two examples of polyatomic cations are the ammonium (NH4+) and the methylammonium (CH3NH3+) ions. P. The method used to predict the empirical formulas for ionic compounds that contain monatomic ions can also be used for compounds that contain polyatomic ions. The overall charge on the cations must balance the overall charge on the anions in the formula unit. Thus, K+ and NO3− ions combine in a 1:1 ratio to form KNO3 (potassium nitrate or saltpeter), a major ingredient in black gunpowder. Similarly, Ca2+ and SO42− form CaSO4 (calcium sulfate), which combines with varying amounts of water to form gypsum and plaster of Paris. The polyatomic ions NH4+ and NO3− form NH4NO3 (ammonium nitrate), a widely used fertilizer and, in the wrong hands, an explosive. One example of a compound in which the ions have charges of different magnitudes is calcium phosphate, which is composed of Ca2+ and PO43− ions; it is a major component of bones. The compound is electrically neutral because the ions combine in a ratio of three Ca2+ ions [3(+2) = +6] for every two ions [2(−3) = −6], giving an empirical formula of Ca3(PO4)2; the parentheses around PO4 in the empirical formula indicate that it is a polyatomic ion. Writing the formula for calcium phosphate as Ca3P2O8 gives the correct number of each atom in the formula unit, but it obscures the fact that the compound contains readily identifiable PO43− ions.Summary • There are two fundamentally different kinds of chemical bonds (covalent and ionic) that cause substances to have very different properties. • The composition of a compound is represented by an empirical or molecular formula, each consisting of at least one formula unit.Contributors The atoms in chemical compounds are held together by attractive electrostatic interactions known as chemical bonds. Ionic compounds contain positively and negatively charged ions in a ratio that results in an overall charge of zero. The ions are held together in a regular spatial arrangement by electrostatic forces. Most covalent compounds consist of molecules, groups of atoms in which one or more pairs of electrons are shared by at least two atoms to form a covalent bond. The atoms in molecules are held together by the electrostatic attraction between the positively charged nuclei of the bonded atoms and the negatively charged electrons shared by the nuclei. The molecular formula of a covalent compound gives the types and numbers of atoms present. Compounds that contain predominantly carbon and hydrogen are called organic compounds, whereas compounds that consist primarily of elements other than carbon and hydrogen are inorganic compounds. Diatomic molecules contain two atoms, and polyatomic molecules contain more than two. A structural formula indicates the composition and approximate structure and shape of a molecule. Single bonds, double bonds, and triple bonds are covalent bonds in which one, two, and three pairs of electrons, respectively, are shared between two bonded atoms. Atoms or groups of atoms that possess a net electrical charge are called ions; they can have either a positive charge (cations) or a negative charge (anions). Ions can consist of one atom (monatomic ions) or several (polyatomic ions). The charges on monatomic ions of most main group elements can be predicted from the location of the element in the periodic table. Ionic compounds usually form hard crystalline solids with high melting points. Covalent molecular compounds, in contrast, consist of discrete molecules held together by weak intermolecular forces and can be gases, liquids, or solids at room temperature and pressure. An empirical formula gives the relative numbers of atoms of the elements in a compound, reduced to the lowest whole numbers. The formula unit is the absolute grouping represented by the empirical formula of a compound, either ionic or covalent. Empirical formulas are particularly useful for describing the composition of ionic compounds, which do not contain readily identifiable molecules. Some ionic compounds occur as hydrates, which contain specific ratios of loosely bound water molecules called waters of hydration.

The LMS has been an essential tool in curriculum design and development and in organizing factors that motivate student learning, especially in online distance learning. However, an LMS can be used in blended, hybrid, and in-class delivery modes. It is a software application designed to help in the administration of courses for both students and instructors. Such systems have been designed for use in learning and teaching activities (Chung et al., 2012). They also provide a variety of interaction methods between instructors and learners to facilitate the learning process better, You must remember well-designed LMS could also help improve student skills, such as effective online learning and self-direction (Norouzi, 2014). Students could use the system to enhance performance (perceived usefulness), and they could use such systems with little effort (perceived ease of use) (Venkatesh & Davis, 2000). A majority of higher education institutions have incorporated LMS systems; they have been used in university systems by schools, faculty members, and instructors (Klobas & McGill,. 2010), Because so much of higher education has been focused on course delivery Chapter3 INSTRUCTIONAL DELIVERY SYSTEMS AND EDUCATIONAL TECHNOLOGY i 71 in a physical classroom, the implementation of an LYS has a;ded institutons in transitioning to new online universe of curriculum de!ivery (Georgou!i, & Guerre. 2NS). Repositories, central databases, and online meeting 'oations are all characteristcs of a management system. As a concept, a 'earning management system is a broad idea and an example of technology's inabifity to be specific in terms of a definition. Several requirements a generat overview of what constitutes a leaming management system, such as those listed above Finally, end-user access is also a part of a learning management system with various levels being set up by security. For example, students have read-onty access, faculty members have read and write access, and technical staff has complete access for support and administrative duties (Graf & Chien, 2009). At its core, a learning management system contains internal or Web-based support and management for numerous aspects of learning and teaching (Hiary & Abu-Shawar, 2009). This allows access from numerous locales, usually on a 24-hour basis. When looking at a university or college, this concept begins to grow greatly depending on the organization's size and scope; department, and degree program. Leaming management systems also go by other names such as course management systems, and their use goes beyond higher education institutions to include businesses and individual instructors. Meis)ar-Tal, Kurtz, and Pieterse (2012) mentioned three primary purposes of an CMS. They include the following: 1. to provide students with digital learning materials; 2. to employ interactive learning activities with students in the forums; and 3. to manage the course and the learners. Faculty members who use an LMS to make available lecture notes and other classroom resources for their face-to-face class create a web-enhanced classroom experience. Regardless of its usage, requirements for classification as a learning management system include several key concepts like the availability of assets over networks, providing hosting, administration. and support. With the requirements set, utilization becomes the focal point. A fully utilized learning management system looks at use at the student level, faculty level, and administration level. proper utilization of learning management systems should mirror traditional higher education goals, enhancing students' experiences. For learninä management systems, this creates a central hub for a class activity. For some classes, all activities work in the learning management system, while others only use its resources for select activities.

Write reading comprehension questions based on the text: Apple's design genius. I've always loved great design. Ever since I can remember I've been fascinated by the shape and look of objects. In n opinion, Apple Inc. is the number one company in the world for product design. In the time that 'you're reading this article, around 750 iPhone and 300 iPads will be sold internationally. These iconic devices generate millions of pounds a day for Apple, and the man behind their iconic look is known as a 'design genius'. In 2013, Time Magazine listed him as one of the 100 most influential people in the world, but can you name him? If you said Steve Jobs, you'd be wrong, although it was Jobs who first recognised this man's talent. His name is Jony Ive. Born in London, Jony Ive studied industrial design at Newcastle Polytechnic. After graduating, he helped set up the London design agency Tangerine. In 1992, while he was working at Tangerine, he accepted a job offer from Apple. His first years in the job were tough and the design work wasn't very interesting. The company was also struggling to make money. However, when Steve Jobs returned to Apple in 1997 and saw the design work that Ive had produced, he immediately recognised Ive's ability and promoted him. Ive's first success in his new role was the design of the original, colourful iMac in 1998, which was quickly followed by the first iPod in 2001. Thanks to Ive's simple, elegant designs, Apple became one of the most successful companies in the world. Since then, he has been responsible for the iPhone, iPad and Apple Watch. Ive's design involves not only the way these products look but also the way they work. He believes devices have to be both beautiful and practical. Jony Ive's key contribution to Apple is now being recognised and he has received numerous awards. There is no doubt that Steve Jobs was a larger-than-life ideas man and businessman who created a hugely successful company. However, without Jony Ive's design talent, Apple may not have become such a huge success. So what have I learnt from Jony Ive? That the best designs are often the simplest.

Solomon was the son of David. His mother’s name was Bathsheba. He became king after King David. He was the third king of Unified Israel. When he became king, he prayed to God for wisdom to rule the people of Israel. God responded to Solomon’s prayer for wisdom by granting Solomon wisdom, riches, and honour, as a result, he became a great leader and was the wisest man who ever lived. Knowledge consists of facts or ideas acquired by study, observation, or experience. Wisdom refers to the ability to make good decisions based on knowledge. James 1:5-6 states that anyone who lacks wisdom should ask God for it because He gives generously to all who ask in faith. Godly wisdom is more valuable than earthly riches and treasures. Solomon wrote proverbs so that people could learn godly wisdom, discipline, and discernment. Simply knowing the difference between right and wrong is not enough. A person must also listen to God, act on knowledge and godly wisdom, and choose to obey God. Psalm 111:10 teaches that fearing the Lord is the beginning of wisdom. Wisdom becomes part of a believer's life once he or she learns to fear and revere the Lord. Applying God's Word to everyday life is the foundation for wise living. Solomon wrote 3,000 proverbs and composed 1,005 songs; he was a scientist with great knowledge of many plants and animals.

好的，根據您提供的表格 [NEW SOURCE]，以下是表格中例句的中文意思： * **1. all** * **全部的**：**All** my friends were here with me. (我所有的朋友當時都在這裡。) * **全部**：**All** of us enjoyed the movie. (我們所有人都很喜歡這部電影。) * **都**：He got **all** wet. (他全身都濕透了。) * **2. along** * **沿著**：We walked **along** the river yesterday evening. (我們昨天傍晚沿著河邊散步。) * **帶……一起**：When my mother goes out, she takes my little brother **along**. (我媽媽外出時，會帶著我的小弟弟一起去。) * **3. angle** * **觀點**：We should look at the problems from different **angles**. (我們應該從不同的觀點來看待這些問題。) * **角度**：The picture is hanging at an **angle** of 45°. (這張畫以 45 度的角度懸掛著。) * **4. answer** * **答案**：Do you know the **answer** to the question? (你知道這個問題的答案嗎？) * **回答；回應**：Could you **answer** the phone for me? (你可以幫我接一下電話嗎？) * **5. back** * **後面**：She wrote her cellphone number down on the **back** of the paper. (她把她的手機號碼寫在紙的背面。) * **後面的**：Open the **back** door, please. (請打開後面的門。) * **回原處**：It’s time to go **back** home. (該回家了。) * **6. bat** * **蝙蝠**：Did you ever see a **bat** flying quickly in the sky at night? (你曾經看過蝙蝠在夜空中快速飛行嗎？) * **球棒**：Swing the **bat** higher. (把球棒揮高一點。) * **擊**：It’s your turn to **bat**. (輪到你打擊了。) * **7. bite** * **一口的量**：Jane took a **bite** of the guava. (珍咬了一口芭樂。) * **咬**：The dog **bit** the woman’s leg. (那隻狗咬了那個女人的腿。) * **8. book** * **書**：I’ve just started reading a **book** by Stephen King. (我剛開始讀一本史蒂芬·金的書。) * **預訂；預約**：They **booked** two seats at the theater. (他們在劇院預訂了兩個座位。) * **9. block** * **街區**：Nancy and I live on the same **block**. (南希和我住在同一個街區。) * **阻擋**：Those heavy boxes **blocked** my way to the restroom. (那些沉重的箱子擋住了我去洗手間的路。) * **10. bow** * **蝴蝶結**：David chose a gray **bow** tie to go with his black suit. (大衛選擇了一個灰色蝴蝶領結來搭配他的黑色西裝。) * **鞠躬**：The actor **bowed** to everyone before he left the stage. (那位演員在離開舞台前向大家鞠躬。) * **11. break** * **暫停；休息**：I’m tired. Can we take a **break**? (我累了。我們可以休息一下嗎？) * **分解**：These plastic forks are hard to **break** down. (這些塑膠叉子很難分解。) * **打破**：The glass is very expensive. Don’t **break** it. (這個玻璃很貴。不要打破它。) * **12. bright** * **晴朗的**：It’s a **bright** morning. Why not take a walk along the river? (這是個晴朗的早晨。何不沿著河邊散步呢？) * **明亮的**：The room isn’t **bright** enough. Let’s not read here. (這個房間不夠明亮。我們不要在這裡閱讀。) * **13. call** * **打電話**：I got a **call** from my old friend last night. (我昨晚接到我老朋友的電話。) * **打電話**：Tina **called** me last night. We talked a lot about music. (蒂娜昨晚打電話給我。我們聊了很多關於音樂的事。) * **呼喊**：Listen! Is that a **call** for help? (聽！那是求救的呼喊嗎？) * **呼喊**：Why did you **call** my name then? (那你當時為什麼喊我的名字？) * **14. camp** * **營隊**：Patrick joined a science **camp** this summer. (派屈克今年夏天參加了一個科學營隊。) * **露營**：They **camped** by the river yesterday. (他們昨天在河邊露營。) * **15. case** * **箱；盒**：The kids drank the whole **case** of Coke. (孩子們喝掉了一整箱可樂。) * **實例；情況**：The number of new **cases** of Covid-19 is growing. (新冠肺炎的新增病例數正在增加。) * **16. catch** * **接球**：Nice **catch**! My good dog. (接得好！我的好狗狗。) * **罹患（病）**：My head hurts. I may **catch** a cold. (我頭痛。我可能感冒了。) * **抓住**：I didn’t **catch** the ball. (我沒有接到那個球。) * **17. change** * **零錢；找零**：I think you’ve given me the wrong **change**. (我想你找錯錢了。) * **改變；交換**：The leaves **change** (in color) from green to red in the fall. (秋天時，樹葉的顏色從綠色變成紅色。) * **18. clean** * **打掃；清理**：Tom **cleans** the toilet once a week. (湯姆一週打掃一次馬桶。) * **乾淨的**：The water isn’t **clean**. Don’t drink it. (這水不乾淨。不要喝。) * **19. close** * **關；闔**：**Close** your books, students. Let’s have a pop quiz. (同學們，把你們的書闔上。我們要進行隨堂測驗。) * **靠近地**：Jane sat **close** to her husband at the party. (在派對上，珍緊挨著她的丈夫坐著。) * **20. cold** * **感冒**：I had a **cold** a week ago. (我一個星期前感冒了。) * **寒冷的**：It was **cold** last night. (昨晚很冷。)

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