21 . ________evidence that language acquiring ability must be stimulated.

　　A. If being

　　B. It is

　　C. There is

　　D. There being

　　C 句中有连词that和谓语must be stimulated，缺少一个谓语动词，排除A,D，该句译成汉语是"有。。。的证据",而不是"它是。。。的证据"所以排除B

　　22. Professor Wang , _______ for his informative lectures, was warmly received by his students.

　　A. knowing

　　B. known

　　C. to be known

　　D. having known

　　B

　　23.In fact Peter would rather have left for San Francisco than ____ in New York.

　　A. to stay

　　B. stayed

　　C. stay

　　D. having stayed

　　C

　　24.You ____ him so closely; you should have kept your distance.

　　A. shouldn't follow

　　B. mustn't follow

　　C. couldn't have been following

　　D. shouldn't have been following

　　D

　　25.There has been a great increase in retail sales , ____﹖

　　A. does there B. isn't there

　　C. hasn't there D. isn't it

　　C

　　26. It is the news ____ most parents of the hope that there is a safe and socially approved road to a kind of life they themselves have not had, but their children can.

　　A. that deprive

　　B. that it deprives

　　C. that deprives

　　D. when it deprives

　　C

　　27. We hadn't met for 20 years, but I recognized her_____ I saw her.

　　A. the moment

　　B. for the moment

　　C. the moment when

　　D. at the moment when

　　A 定冠词the加上表示时间的名词起连词作用，引导时间状语从句。如the night/ the minute/ the spring/ the year等。

　　28. On hearing a great noise, Mike looked forward through the window _____ what happened outside the room.

　　A. to seeing

　　B. to see

　　C. seeing

　　D. to have seen

　　B look forward to doing sth. / sth. 表示"盼望做某事"，而look forward to do sth.表示向前看目的(要做。。。)

　　29. You ______ be driven out of the school if you dare to cheat in the exam.

　　A. should B. would

　　C. will D. shall

　　D shall用于第二，三人称表示说话人的心愿; will表示主语的心愿。

　　30. Everyone hopes that we can do something to make things better, so we can't help ______ under the stress.

　　A. but working

　　B. but to work

　　C. work

　　D. but work

　　D can't help but do…相当于 have to do….。

　　31. We all think that _____ no need to make laws to prevent the young from getting married during their college life.

　　A. it is B. there has

　　C. it has D. there is

　　D There is no need (for sb.) to do sth.是一个固定句型，相当于 It is unnecessary ( for sb.) to do …;或 sb. have no need to do sth..

　　32. Postage ___ the necklace will cost you at least 650 yuan.

　　A. including B. included

　　C. include D. to be included

　　B postage included 等于including postage。

　　33. With his eyes ______ on the family album, he thought of the fun he had when he lived with his parents.

　　A. fixing B. fixed

　　C. to be fixed D. being fixed

　　B fix one's eyes on / upon 是固定短语，表示"注视"

　　34. George applied for the position three times ______ he finally got it.

　　A. before B. until

　　C. when D. after

　　A 强调从句中谓语动词的动作发生的晚，表示"。。。。。。才。。。。。。"。

　　35. This robot is supposed to save a lot of labor, but it remains a problem if it ______

　　A. is B. saves

　　C. does D. has

　　C do(es) 是代动词，用来代替上文save a lot of labor。

　　36. There were many more people who got injured in the big fire than _______.

　　A. was reported

　　B. it was reported

　　C. were reported

　　D. they were reported

　　A 比较状语从句中省略与主句相同的成分，只保留比较对象。

　　37. He doesn't know what to say, for it is the first time that he ______ with a girl.

　　A. went out

　　B. goes out

　　C. has gone out

　　D. had gone out

　　C

　　38. ___which way to take, the little boy behaved like a real gentleman who comforted his sister from time to time.

　　A. Leaving to wonder

　　B. Having left to wonder

　　C. Left wondering

　　D. Left to wonder

　　C left wondering 中left的逻辑主语是the little boy，所以可转换成The little boy was left wondering…。

　　39. During the tourist season, there are many people wandering in this city to see the old castles _____ in the sixteenth century.

　　A. to be built

　　B. being built

　　C. having been built

　　D. built

　　D 非谓语动词的动作先于句中谓语动词的动作时， 用过去分词。