虚拟语气表示说话人的愿望、假设、猜测或建议，而不表示客观存在的事实。虚拟语气通过谓语动词的特殊形式来表示。下面对虚拟语气在各种句式中的用法分别介绍。
（一）虚拟语气用于条件状语从句
1.表示与现在事实相反的假设时，条件状语从句中的谓语动词用“过去式(be的过去式用were)”．而主句中的谓语动词用"would (should, could，might)＋动词原形.”例如：
If I were you, I should study English.
If he had time，he would attend the meeting.
2.表示与过去的事实相反的假设时，条件状语从句的谓语动词用“had+过去分词”，主句中的谓语动词用 “would (should, could, might)＋have＋过去分词”．例如：
If you had taken my advice，you wouldn't have failed in the examination.
3．表示与将来事实相反的假设时．条件从句和主句所用的谓语动词与“表示现在事实相反的假设” 的谓语动词相同，或者条件从句中用“were to(should)＋动词原形”．例如：
If you came tomorrow，we would have the meeting.
If it were to rain tomorrow, the meeting would be put off.
4.当条件状语从句表示的行为和主句表示的行为所发生的时间不一致时，动词的形式要根据它所表示的时间来调整。例如：
If you had worked hard，you would be very tired.（从句说的是过去，主句指的是现在。）
5.以上句型可以转换成下列形式：
（1）省略if, 用 "were, had, should+主语"。如：
Were I in school again, I would work harder.
Had you been here earlier, you would have seen him.
Should there be a meeting tomorrow, I would come.
但在虚拟条件状语从句中，省略连词的倒装形式的句首不能用动词的缩略形式。如我们可以说：Were it not for the expend, I would go to Italy.但不能说：Weren't it for the expense, I would go to Italy.
(2)用介词短语代替条件状语从句。例如：
Without air, there would be no living things.
But for your help, I couldn't have done it.
(3)用其他方式表示。例如：
It would produce bad results to do that.＝If you have done that，it would produce bad results.
(二)虚拟语气用于宾语从句
1．“wish+宾语从句”表示不能实现的愿望．汉语可译为“可惜……”“……就好了”“悔不该….”“但愿…”等。表示现在不能实现的愿望， 从句的谓语动词用过去时；表示将来不能实现的愿望用“would(could)+动词原形”；表示过去不能实现的愿望用“had＋过去分词”或（could）＋have done．例如：
I wish you could go with us.
We wish we had arrived there two hours earlier.
2. 虚拟语气在动词 arrange, command. demand, desire, insist, order, request, require, advise, suggest, recommend, propose,等后面的宾语从句中用“(should)+do".例如：
We suggested that we（should) have a meeting.
We insisted that they（should) go with us.
The doctor ordered that she（should) stay in bed for a few days.
He demanded that we（should) start right away.
注意:insist作“力言”“强调”解时，宾语从句不用虚拟语气。只有当insist作“坚持（认为）”“坚持（应该）”解时宾语从句才用虚拟语气。例如：Mike insisted that he had never stolen anything.
3．虚拟语气在动词mind中的使用
Would you mind if I smoked here?
4. 虚拟语气在动词would rather 中的使用
I would rather I were at home now.
I’d rather he hadn’t done such foolish things.
(三) 虚拟语气用于表语从句、同位语从句作advice idea, order, demand, plan, proposal，suggestion, request等名词的表语从句和同位语从句时，其谓语动词要用虚拟语气的结构“（should)＋动词原形”．例如：
We all agreed to his suggestion that we (should) go to Beijing for sightseeing.
My idea is that we（should）do exercises first.
(四)虚拟语气在as if (as though),even if (even though)等引导的表语从句或状语从句中的应用
如果从句表示动作发生在过去，用过去完成时；指现在状况，则用过去时；指将来则用现在将来时．例如：
He looked as if he were an artist.
He speaks English so fluently as if he had studied English in England.
Even if he were here，he could not solve the problem.
(五) 虚拟语气用于主语从句在主语从句中，谓语动词的虚拟语气结构“should+动词原形”的结构，表示惊奇、不相信、惋惜、理应如此等。例如：It is necessary (important, natural, strange, etc.) that .... we should clean the room every day.
It was a pity (a shame, no wonder, etc.) that you should be so careless.
It will be desired (suggested, decided, ordered, requested, proposed, etc.) that she should finish her homework this afternoon.
在上述三种主语从句中，should意为“应该”“竟然”，可以省去，但不可换用would。主句所用动词的时态不限。注意：这种从句表示的是事实。如果说话人对这种事实表现出惊奇的情感，就可用虚拟语气．反之。如果不表示惊奇等情感,that从句也可用陈述语气，例如：
It is strange that he did not come yesterday.
It is a pity that you can't swim.
(六）虚拟语气用于定语从句这种从句常用在It is (high) time(that)…句型中，定语从句的谓语动词用过去式，或should+动词原形(should不能省略，be用were)来表示，意为“(现在）该……”。例如：It is（high) time we left（should leave)．
It is high time we were going.
（七）虚拟语气用于if only引导的感叹句中
If only I had taken his advice.我要是听他的话就好了。
If only I were a bird.我如果是一只鸟就好了。
（八) 虚拟语气在简单句中的应用
1)情态动词的过去式用于现在时态时,表示说话人谦虚，客气，有礼貌或语气委婉，常出现在日常会话中，例如：It would be better for you not to stay up too late.
Would you be kind enough to open the door?
(2)用于一些习惯表达法中，例如：Would you like a cup of tea?
I would rather not tell you.
You had better go now.
(3)用“may+动词原形”表示“祝愿”“但愿”。
May you be happy！
May you succeed!
虚拟语气练习
1．I didn’t see your sister at the meeting. If she ____, she would have met my brother.
A. has come B. did come C. came D. had come
2. -Where ____?
-I got stuck in the heavy traffic, otherwise I ____ here earlier.
A. did you go; had arrived B. have you been; would have been
C. were you; would come D. are you; would come
3. He ____ full marks, but he was so careless as to make some spelling mistakes.
A. must have gained B. can have gained C. could have gained D. must gain
4. Without the air to hold some of the sun’s heat, the earth at night ____, too cold for us to live on.
A. would be freezing cold B. will be freezing coldly
C. would be frozen cold D. can freeze coldly
5. ____ the fog, we should have reached our school on time.
A. Because of B. In spite of C. In case of D. But for
6. ____ it rain tomorrow, we would have to put off the visit to the Yangpu Bridge.
A. Were B. Should C. Would D. Will
7. ____ to do the work, I should do it some other way.
A. If were I B. I were C. Were I D. Was I
8. Had you taken the doctor’s advice yesterday, you ____ all right now.
A. are B. were C. would be D. would have been
9. If only I ____ some English, but I know nothing of it.
A. know B. knew C. known D. has known
10. He suggested that we ____ a meeting to discuss the problem and the worried
look on his face suggested that he ____ anxious to solve the problem.
A. should hold; was B. had done; should be set
C. do; be set D. should hold; should be
11. The young man insisted that he ____ nothing wrong and ____ free.
A. did; set B. had done; should be set
C. do; be set D. had done; must be set
12. I would have telephoned her, but I _____ her number.
A. hadn’t know B. didn’t know
C. don’t know D. wouldn’t have known
13. Given a few more hours, they ____ the work that day.
A. would fulfil B. would have fulfilled
C. had fulfiled D. fulfiled
答案：1-5 DBCAD 6-10 BCCBA 11 BBB
虚拟语气练习
1. He wished that he ___ the examination the next day.
A. would pass B. will pass C. passed D. has passed
2. With better equipment, we ___ the job even sooner.
A. would finish B. might finish
C. could have finished D. had finished
3. It __ only partly right to answer in this way.
A. will be B. would be C. is D. may be
解析：to answer in the way =if we answer in this way
4. Everything taken into consideration, they ___ their output quickly.
A. would have raised B. can have raised
C. must have raised D. would raise
5. It seems as if it ___ already summer.
A. is B. were C. be D. should be
6. They both talked as if they ___ friends before.
A. should be B. had been C. would be D. have been
7. Had she found it, she ___ it.
A. would have sent B. sent C. should send D. send
8. I’d rather you ___ right away.
A. leave B. left C. should leave D. will leave
9. Without the Communist Party of China, ___New China.
A. there were not B. there would be no
C. there will be D. there hadn’t been
10. Long ___ the Communist Party of China!
A. should live B. will live C. live D. lived
11. If you ___ the doctor’s advice, you ___ quite all right now.
A. had followed; were B. had followed; would be
C. had followed; would be D. followed; would be
12. We propose that Mr White ___ the chairman.
A. be B. must C. will be D. is
13. Zhao Xin insisted that he ___ anything at all.
A. shouldn’t steal B. hadn’t stolen
C. not steal D. didn’t steal
14. We agreed to the plan that he ___ Hong Kong this summer.
A. had visited B. would visit C. visit D. could visit
15. Meeting anywhere else, we ___ each other.
A. wouldn’t have recognized B. should recognize
C. could have recognized D. recognized
16. The production ___ up still more rapidly under the more favorable conditions.
A. would have gone B. will have gone
C. should go D. must have gone
17.You could have passed the exam, ___ you spent most of your time playing and reading useless books.
A. if B. or C. but D. unless
18.-Hi, Sam! You are late.
-Sorry. I would have come sooner, but I ___ that you were waiting.
A. didn’t know B. know
C. hadn’t known D. haven’t known
19. One of the requirements for the fire is that the material ____ to its burning temperature.
A. is heated B. will be heated C. would be heated D. be heated
20. If he _____ that he _____ to work there, everything would be OK now.
A. insisted; be sent B. insisted; was sent
C. had insisted; be sent D. had insisted; was sent
21. My demand is that the information referred to in my report ____ to Mr. Brown without delay.
A. to be e-mailed B. e-mailed C. be e-mailed D. being e-mailed
22. I don’t think it advisable that Jack _____ the job since he has little experience.
A. is given B. will be given C. be given D. has been given
23. -Why didn’t Tom give you one of his paintings?
-I didn’t want one, but he would have given me one if I _____.
A. do B. would C. will D. had
24. I’d rather you did some housework when you are free, but you ____.
A. didn’t B. shouldn’t C. weren’t D. don’t
25. This time Tom _____ careful enough, otherwise he would not have passed the test.
A. will be B. was C. had been D. were
答案：1-5 ACBAB 6-10 BABBC 11-15 CABCA 16-20 ACADC 21-25 CCDDB
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