51.The pen _________ him ten yuan.

　A. paidB. costC. tookD. spent

　答案：B　(选择C的同学要注意took通常用在时间上；选择A和D的同学要注意，这里的主语是物品，因此不能用paid 和spent)

50..He will call me as soon as he _________ the city.

　A. reachesB. reachedC. will reachD. is reaching

　答案：A　(选择B的同学要注意主将从先)

49..If you have lost a library book, you have to _________ it.

　A. find outB. look afterC. pay forD. take care

　答案：C　(选择A的同学要注意语境)

48.– I called you last night but no one answered the phone.

　-- I ________ dinner with my friends in the restaurant.

　A. haveB. hadC. was havingD. have had

　答案：C　(选择B和D的同学要注意分析语境.这里指我当时正在和朋友在饭馆吃饭.)

47..If anyone wants to say something in class, you ________ put up your hands first.

　A. mustB. mayC. shouldD. can

　答案: A ( 选其他三个选项的同学要注意语境，anyone暗示出语气。表明是一个规定，而不是建议。)

46.It is in the library, you _______ talk loudly.

　A. may notB. can’tC. needn’tD. mustn’t

　答案: D ( 选择B的同学要注意中文的干扰.can’t表示不能够。)

45..Though it’s cloudy now, it _________ get sunny later.

　A. can B. mayC. mustD. need

　答案: B ( 选C的同学要注意语境, 这里强调过些时候也许会晴天, 表示推测性.)

44.– Must I finish it now?

　-- No, you ________.

　A. mustn’tB. needn’tC. can’tD. shouldn’t

　答案: B (选择A的同学要注意mustn’t意思指不允许, needn’t指的是不必要.)

43..-- __________ you ________ your book to the library?

　-- Yes. I returned it yesterday.

　A. Did, returnB. Have, returnedC. Will, returnD. Do, return

　答案: B ( 选择A的同学过分注意回答用了一般过去时, 但在上一句中, 并没有给出过去的时间,强调你现在是否还书了, 应用现在完成时.)

42..It’s spring now. The students ________ trees these weeks.

　A. plantB. are plantingC. will plantD. planted

　答案: B (选择A的同学要注意 these weeks 并不表示经常做某事,而是强调这几个星期同学们一直在种树.)