A number of books in the library ____ been stolen so that the number of them ____ smaller than before.
_______ on the American Civil War, the book attracted a large number of readers when it was published.
I haven’t seen Li Lei these days. He was said _____ to the hospital to receive treatment.
—Do you mind my closing the door? It’s a little bit cold in here. —___________.
Lucy couldn’t remember when she met Tom, but she was sure it was on ______Monday when she had ______ music class.
I ______ an old letter while I was searching my drawer.