20．I was really anxious about you. You ________ home without a word.

　A. mustn't have left B. oughtn't to leave　C. oughtn' t to have left D. shouldn't leave

19．--I left my watch on the desk, but now it's gone.--Who do you think ________it?

　A. having taken　　 B. to have taken　 　C. has taken　　　　　 D. took

18．--Correct ___ is important.--I agree. I don' t eat sweets now, for I'm on a_____.

　A. diet; diet　　 B. food; diet　 　C. diet; food　　 D. food; food

17．_______ an atom is broken up , it may _______ another atom to break , too .

　A．When ; cause　 B．As ; make　C．While ; cause　　 D．Since ; cause

16．You'd better not wake me up when you come in,　 ________ ?

　A. had you　　 B. hadn't you　 C. wouldn't you　 D. would you

15．-Take this medicine three times a day , and you _________ soon .　-_________.

　 A．are right ; Thank you　B．will be quite yourself ; It’s kind of you

　C．will be all right ; Thank　D．are feeling better ; You’re welcome

14．It is quite ________ that many nutrients can help keep our body functioning well. Vitamins, fibre and minerals help keep our body fight diseases and give us energy.

　A. surely　　　 B. sure　　　　 C. certain　　　 D. exact

13．New York is a city larger than _______ in the USA .

　A．any city　B．any cities　　　C．any other cities　D．any other city

12．Many fruits are ________ Vitamin(维他命)C .

　A．rich with　 B．rich for　　C．rich on　　 D．rich in

11．It is not good to drink _________ coffee .

　A．too much　B．much too　　C．too little　　D．little too