20. Don’t _______ call me if you need any help.

A. think of　　 　　　 B. remember to　　　 　 C. try to　　　　　 　　　 D. hesitate to

19.--I must apologize for _________ahead of time.

　 　--That’s all right.

A. letting you not know　　　　　　　 B. not letting you know

C. letting you not　　　　　　　　　　 D. letting not you know.

18.-- Haven’t I told you that the computer wants ______?

--Sorry, I forgot _______ it fixed. I’ll send it for repairs right away.

A. repairing; to have　　　　　　　 　　　　B. to repair; to have

C. repairing; having　　　　　　　　 　　　　D. to be repaired; having

17. Mr. Smith, _____of the _____ speech, started to read a novel to kill time.

A.　tired; boring　　　 B. tiring; bored　　 　 C. tired; bored　　　 D. tiring; boring

16. There is no ________ to worry, Mum. Everything will ________ to be all right.

　　　　　 A. way; turn up　　 B. need; turn out　　　　　 C. excuse; turn down 　　 D. chance; turn in