21.Chinese customs police wondered if there were some underground passages____ the cocaine had been smuggled into China from Burma.

A. through which 8 . in which C. through that D. in that

22.Just think of it! If you can memorize ten English words____ , what a big vocabulary you'll have in a year 's time.

A. everyday B. every day C. one day D. someday

23. They_____ the problems with the principal himself had the parents gone to the meeting.

 

A. had discussed   B. could discuss  C. could have discussed  D. would discuss

 

24. Giant corporations, to dominate the United States economy in the late nineteenth century, grew steadily during the l 920's.

 

A. which began  B. in which began C. they began  D. which they began

 

25. One of the basic principles of wildlife conservation involves______ adequate natural food and shelter to maintain populations of each species in a given habitat.

A. the provision B. that prov1s10n C. to provide D. providing

26. By focusing on the interesting , ______the significant, the penny press newspapers of the 1830's helped to change the concept of news.

A. which does not necessarily B. not necessarily C. was not necessarily D. nor necessarily being

27.He is very popular among young people . They regard him______ as other musicians.

A. more superior to B. the most superior C. superior to D. superior than

28. Arriving early for the concert is better than_____ the chance of being late.

A. to take B. if taking C. take D. taking

29.  Inasmuch as a year does not elapse without a certain number of villagers falling victim to the ferocity of a tiger, its roar is ____heard by the natives______ feelings of terror.

 

A. not...with  B. always... without   C. seldom . . .with    D. not... without

 

30.A television camera produces an image by converting receives into a series of bright and dark dots.

A. and it B. it C. what it D. that it