21. He was very busy yesterday; otherwise he______ to the meeting. (QE93-21)

        A. would have come   B. would come   C. could come       D. had come

        【答案】A 本句考察虚拟语气。“如果他不是很忙的话，昨天就去开会了”，事实是他没有去开会，所以是与过去事实相反的假设，主句应该用过去将来完成时，因此选A项would have come.

        22. Without your help, we ____ so much. (QE96-33)

        A. didn’t achieve   B. would not have achieved   C. will not achieve   D. don’t achieve

        【答案】B 本题考察的是虚拟语气. without your help = if you had not helped us,表示与过去事实相反,主句谓语动词用should/would/could/might + 动词原形.故选B. 句意是“如果不是你帮助我们,我们就不会取得这么大的成就.”

        23. Something must have happened on their way here. Or they ___ by now. (QE02-47)

        A. should have arrived   B. should arrive   C. would have arrived  D. would arrive

        【答案】C。第一句是must+have +过去分词的结构，表示对过去事实的推测。The road is wet. It must have rained last night.路是湿的，昨晚上肯定下雨了。因此我们可以推断：这是一个和过去的事实相反的虚拟语气。should +have +过去分词的结构，表示对过去动作的责备、批评。如：You should have gone over your lessons.你应当把功课复习好的。但是此句只是一个表示和过去的事实相反的虚拟句子，并没有责备的意思。本句的意思是：“路上肯定出事了。否则，他们现在已经到了。”因此正确答案应该是C.

        24. But for the rain, we ____ a nice holiday. (QE03-04-48)

        A. should have    B. would have had   C. would have    D. will have had

        【答案】B 这是含蓄条件句，表示“如果不……则我们已经……了”，故选B。but for：如果不是因为……，要不是……。句意为：如果不是因为下雨，我们本可以好好度假。Would have done 表示对过去事实的虚拟。

        25. But for my classmates’ help, I ___the work in time. (QE04-04-36)

        A. did not finish    B. could not finish     

        C. will not finish    D. would not have finished

        【答案】D  此句是含有含蓄条件句“but for my classmate's help"的句子.因此要选择一个虚拟语气的句子。因为是和过去的事实相反,因此D为正确答案。本句的意思是：“要不是同学们的帮助．我是不会按时完成任务的

        26. If you_____ that late movie last night, you wouldn’t be so sleepy. (QE93-60)

        A. hadn’t watched            B. haven’t watched

        C. wouldn’t have watched      D. didn’t watch

        【答案】A 此题考察虚拟语气，假设“如果你昨晚没看那场电影”，事实是看了，因此句意与过去事实相反，用过去完成时。

        27. If he ___ to the teacher attentively, he ___ the answer to the problem now.

        A.  had listened, would have known   B.  listened, would know  

        C.  listened, would have known      D.  had listened, would know 

        【答案】D。如果他认真听了课，他就会知道这个问题的答案了。错综虚拟语气，前半句对过去，后半句对现在。

        28. ---- I thought you would come back tomorrow.

        ---- I would if I ___ to attend a meeting.

        A.  don’t have  B.  didn’t have   C.  will not have   D.  would not have

        【答案】B。我以为你明天才回来呢。要是不用开会，我就明天回来了。If从句对现在虚拟。

        29. Had you listened to the doctor, you _____ all right now.

        A. are    B. were    C. would be    D. would have been

        【答案】C。如果你听了医生的话，你现在就已经好了。前面对过去，后面对现在。

        30. It is hard for me to imagine what I would be doing today if I ________ in love, at the age of seven, with the Melinda Cox Library in my hometown.

        A. wouldn't have fallen               B. had not fallen

        C. should fall                       D. were to fall

        【答案】B。如果我没有在7岁的时候迷上Melinda Cox图书馆，很难想像我现在在做什么。