23. We must do something to _____ factories _____waste water into the river before it is cleaned.

A. stop; pouring . B. prevent; to pour C. keep; pouring D. stop; to pour

22. What way are you thinking of _____ rid of the flies?

A. to get B. getting C. being got D. to be getting

21. Jack is a good friend _____, he often comes to our home for a visit.

A. of my father B. of my father's C. for my father D. with my father

20. You can say "He went there _____, not _____."

A. on the car; by car B.on foot; in his car C. by foot; by car D.in his car; by his foot

19. I come to tell you Jack _____ for London next month.

A. is leaving B. is about to leave C. will leave D. would leave

18. --They all agree _____ George. Has the project been passed?

--Who _____ George can make the final decision?

A. except; expect B. except; besides C. but; but D. besides; but

17. We are just _____ calling you up _____ you come in.

A. about; when B. on the point of; while C. on the point of; when D. on the point of; as

16. --How often do you go to the library?--______.

A. In two days B. Every few days C. Each third day D. Every a few days

15. I can't understand it, will you please _____ once more?

A. explain that word B. repeat that word　 C. explain us that word D. explain that word for us

14. Everybody in the little town knew my first teacher, so we had no ____ finding his home.

A. difficulties in B. difficulty with C. difficulty D. difficulty to