What does the idiom "kill two birds with one stone" mean?

What does the idiom "through thick and thin" mean?

"Once in a blue moon" refers to something that happens...

What does the idiom "a piece of cake" mean?

What does it mean to "spill the beans"?

If someone says they are going to "hit the sack", they mean:

What does the idiom "actions speak louder than words" mean?

If someone says they are "on cloud nine", they mean:

The phrase "the tip of the iceberg" refers to:

What does the idiom "kick the bucket" mean?

What does "out of the blue" mean?

If someone says "a penny  for your thoughts", they are asking:

"Better late than never" mean?

The phrase "When it rains, it pours" refers to:

To " cry over spilled milk" mean?