38. The English program normally attracts more than 1,000 students a year, ______ up to half will be from abroad.

A. in which　　　 　　　 　　 B. for whom　　 　 C. with which　　　　　　　 D. of whom

37. Only in the past 50 years, with the revolution in diving equipment, ______ study deep seas closely.

　　　 A. were scientists able to　　　 　　　　　　　　 B. scientists were able to

C. have scientists been able to　　　　 　　　　 D. scientists have been able to

36. Contrast may make something appear more beautiful than it is when　　　　 　alone.

　　 A. seen　　　　　　　　　　　　 　 　　　 B. to be seen

　　 C. being seen　　　　　　　　　　 　　　 　　　 D. having been seen

35. The patient who had suffered from H1N1 insisted on　　　 from others immediately, holding the belief that the disease would infect others．

　　　 A．having isolated　　 B．being isolated　　　 C．to be isolated　　 D．isolating

34. No one knows _______ prevented the fire from spreading.

A. what was it that　 B. what it was that 　C. how it was that　 　 D. why it was that

33. _______ she seems to put on a smiling face every day, she hasn’t really got over the shadow of exam failure.

　 　 A. Because　　　　　　 B. As　　　　　　　　　　 C. Whether　　　　　　 　　　 D. Though

32. I think that something has to be done to stop our air from being polluted, _________?

A. doesn't it　　 　　　 B. hasn't it　　　 　　 C. don't they　　 　 　 　　　 D. haven't they

31. The strike _______ so much violence and trouble finally ended after both sides reached an agreement.

　A. caused　　　　　　　　　　 B. causing　　　　　 C. caused by　　　　　　　　　 D. had caused

30. He was not here. Since he had already had his papers corrected, he _____behind.　

A. needn’t have stayed　 　　　　　　　　　　 B. mustn’t have stayed

C. didn’t need to stay　　　 　　　　 　　　 D. shouldn’t stay

29. ____ several times, but Mary still has no idea of how to do it properly.

A. Being shown　 　 B. Having shown 　 C. Having been shown D. I’ve shown her