who______it be that is knocking at the door —It_______be Father, but I’m not sure.

______ we have confidence and determination, we can win the match

21. Whether you believe what he said_________ what he does in the future.

Japan’s economy _______ in the past twentyyears No one knows how long it ______ before it regains its increase

You are so dependent that I’m afraid you can’t adjust yourself to________alone for a time