You don’t forget when we borrowed that reference book,do you? — I can’t remember now but___ sometime last week? [ ]

Could you come to my party tomorrow evening—Sorry, I have something important to do.—That’s too bad. Maybe ______time.

Look, Sue is over there. — That ____ be her. She is in Canada now.

Chinese people have been using paper for over______ years.

Scientists warn us _____ the need tokeep an eye ____ the greenhouse effect.