41. ---What happened to Tom?

　　---He was crossing the street ____ a motorbike hit him from behind.

　　A. while

　　B. when

　　C. until

　　D. because

　　解析：while表示“在......时候”时不能与瞬间动词连用。hit是撞，瞬间的动作。when “当....时候”可以与瞬间动词连用。until 直到....because 因为，后面两个与题目意思不符合，答案为B.

　　42. ---Dad, what‘s the sea like?

　　---Well, it’s large and full of water. It covers about _____ of the earth.

　　A. one third

　　B. three quarter

　　C. three-fourth

　　D. three quarters

　　解析：我们知道海占了地球的大部分。A是三分之一，与题目不符合。quarter是四分之一，在分子大于一时，分母序数词要用复数，答案为D。

　　43. ---Go and ask the waiter how much_____.

　　---Don't worry. It has been _____.

　　A. does the meal cost, paid for

　　B. the meal costs, paid

　　C. the meal spends, paid

　　D. the meal costs, paid for

　　解析：首先宾语从句用陈述句语序，A可以排除。cost表示某物花多少钱，spend 花费时间或金钱，一般人做主语。pay表示付钱，pay for 为....支付了多少钱。答案是B。

　　44. ---Does the child need any help?

　　---No. He is old enough to _____ himself.

　　A. put on

　　B. wear

　　C. dress

　　D. take care

　　解析：put on 强调穿的动作，wear强调穿着的状态，dress后面接人做主语，dress sb.给某人穿衣，dress oneself给自己穿衣，take care of 照顾。答案为C。

　　45. ---There can be no life on the earth without water.

　　---That‟s right. Water _____ everywhere.

　　A. needs

　　B. is needing

　　C. is needed

　　D. needed

　　解析：本题是没水就没有生命，水在任何地方都被需要，被动语态，答案为C。

　　46. ---Were you late ____the meeting?

　　---No, I arrived there ten minutes______ the meeting started.

　　A. for, before

　　B. at, before

　　C. for, till

　　D. at, after

　　解析：be late for 固定用法 “为......迟到” ---为什么你开会迟到? ---不，我在开会前十分钟到的。答案为A。till 直到 after ...之后，before ...之前。

　　47. ---Excuse me, but I don‘t think you can take photos here.

　　---Sorry I ____ this is no-photo zone.

　　A. don’t know

　　B. didn‘t know

　　C. have no idea

　　D. haven’t known

　　解析：根据题目意思可看出对方是以前不知道这里是不允许照相的区域，用过去时，答案为B。

　　48. ---How many English words had you learned ___ the end of last term?

　　---Around 2000, but I‟ve forgotten most of them.

　　A. by

　　B. at

　　C. to

　　D. on

　　解析：by the end of 到....为止,如果后面接将来时间，主句用将来时，如果后面是现在时间，主句用现在完成时，如果是过去时间，主句用过去完成时。at the end of “在...尽头”后面接时间时，一般用过去时或将来时。答案为A。

　　49. ---Are you learning art now during your spare time?

　　---No. I've stopped _____ Chinese medicine instead.

　　A. to learn

　　B. learning

　　C. learn

　　D. studying

　　解析：---你现在在空闲时间学习艺术吗?---不，我已经停止了，在学中医。stop to do 和stop doing分别表示“停下来去做某事”和“停止做某事”答案为A。

　　50. ---What did you ____ just now?

　　---I _____ you if you could follow me.

　　A. say, said

　　B. speak, asked

　　C. speak, said

　　D. say, asked

　　解析：---你刚在说什么?---我问你你是否能跟我来。say是及物动词，强调说话的内容。speak一般表示说某种语言。强调说的动作。ask询问，打听，请求。答案是D。