One’s back is against the wall: China’s soccer team has its back against the wall and must win tonight's game.
Back to back: There was no more space in the gym, everyone should stand back to back.
Not breathe a word: I won’t breathe a word to your parents. Don’t worry!
One’s eyes are bigger than one’s stomach: When my brother went to the bookstore, his eyes are bigger than his stomach because he bought lots of books.
Chilled to the bone: After watching the soccer game we were all chilled to the bone.
To catch one’s breath: Emily stopped running to catch his breath; he could not run as fast as the deers.
As dry as a bone: I don't think he's been watering these