20. It was quite a serious accident,　　　 caused by careless driving.

　A. which I think was　 B. I think which was

　C. which I think it was　 D. I think which it was

　选A。本题考查由which引导的非限制性定语从句，which替代先行词accident 在定语从句中作主语。I think 是插入语，放在which后面。

19. It was quite a long time　　　 I made it out what had happened.

　A. after　　 B. before　　 C. when　 D. since

　选B。“It + be + 时间名词+before / since”从句句型中，连词before　 与since 混淆。用before引导时，句意是 “过了多久才……”，主句中的be动词为过去时或将来时态；用since引导时，其句间是“自从……以来已经多久了”，主句中的be动词多为现在时(或现在完成时)或一般过去时(此时since从句要用过去完成时)。

18. -Bruce was killed in a traffic accident.

　-　　　 I talked with him yesterday morning!

　A. What a pity!　　　　 B. I beg your pardon?

　C. Sorry to hear that.　 D. Is that so?

　选D。答语的后半部分是感叹句，说明惊讶的原因。D项 “Is that so?” 是用问句的语气表示惊讶；C项与后面的语气不一致，是干扰项。

17. Jane was disappointed that most of the guests　when she　　　 at the party.

　A. left; had arrived　　　 B. left; arrived

　C. had left; had arrived　 D. had left; arrived

　选D。客人在她arrived之前就已离开；过去的过去，用had left。

16. The politician has been warned that he would be getting into great trouble　　　 stick to his standpoint.

　A. were he to　　　　 B. he will

　C. he was to　　　　 D. would he

　选A。表示对将来情况的虚拟，条件从句的形式是：should + 动词原形；were to + 动词原形或一般过去时态。把if去掉，应使用倒装形式，故答案为A。

15. Everyone was on time for the meeting　Chris, who’s usually ten minutes late for everything.

　A. but　　　 B. only

　C. even　　　 D. yet

　选C。本句话的意思是：每个人都准时来参加会议了，甚至经常干什么事都迟到十分钟的 Chris也准时来了。

14. The man we followed suddenly stopped ad looked as if　　 whether he was going I the right direction.

　A. seeing　　　　 B. having seen

　C. to have see　　 D. to see

　选D。 as if 引导的状语从句是一个省略句，只剩下了目的状语to see。

13. -I want to go to the library but I am afraid I am not in the right　　　 .

　-　　　 . Go ahead.

　A. way; No　　　　 B. distance; No

　C. side; Yes　　　 D. direction; Yes

　选D。in the right direction“向着正确的方向”。C项不能构成搭配，其他项与句意不符。

12. -Would you rather come on Friday or Saturday?

　-　　　 .

　A. Yes, of course　　　 B. The other is better

　C. What’s the matter　 D. Either would suit me

　选D。句意为：两者中任何一个都合适。

11. -Did you look up the time of trains to Shanghai?

　-Yes, the earliest train is　　　　 to leave at 5:30 am.

　A. likely　　　　　 B. about

　C. possible　　　　 D. due

　选D。be due to do意为“应该…/预期的”；be about to do 不和时间状语连用；possible主语应为it；而likely与句意不合。