What article is used when readers already know the specific thing being mentioned?

In the sentence 'Sahar is reading _____ book that she borrowed from the library', what is the correct article?

What article should be used in the sentence 'Did you see _____ moon last night?'

Choose the correct article for the sentence: 'Ammar wants to become _____ engineer when he graduates.'

In the phrase 'We need to discuss _____ next steps for the project', which article fits best?

What article should be placed before the word 'advice' in 'I need _____ advice before making this decision'?

In 'We stayed at _____ hotel near the beach', which article should be used?

For the sentence 'I saw _____ beautiful painting at the art gallery yesterday', what is the correct article?

Which article should be used in the sentence 'They visited _____ Eiffel Tower during their trip to the Paris'?