老师让我们自己准备英语语法中虚拟语气的用法在课上来讲,求大家帮忙

需要语法结构,在什么情况下用那种结构,几种结构有什么不同,使用时应该注意什么……

虚拟语气
一. 概念:用来表示说话人的主观愿望或假想所说的是一个条件,不一定是事实,或与事实相反。
二.真实条件句用陈述语气
1.真实条件句表示的假想是真实的或有可能性
2.句型:条件从句(一般现在时)+主句(shall/will+动词原形)
3.注意:当表示真理时,主句谓语动词不用shall/will+动词原形,而直接用一般现在时
三.虚拟语气用于非真实条件句中
1.表示同现在事实相反的假想,可以表示现在,过去或将来的情况
2.表示同过去事实相反的假想
句型:条件从句(过去完成时had done)+主句(should/would have+过去分词)
3.表示对将来的假想
句型:①条件从句为一般过去式;主句为should+动词原形
②条件从句为were+动词原形;主句为would
③条件从句为should+动词原形; 主句为would
4.表示错综复杂的条件
有时,主句与从句的动作发生在不同的时间,一个发生在过去,一个发生在现在。
5.虚拟条件句的倒装
  虚拟条件句的从句部分含有were, should, 或had时, 可省略if,再把were, should或had 移到从句的句首,实行倒装。
6.特殊的虚拟语气词should
1)在主语从句中的应用
It is demanded / necessary / a pity + that…等结构的主语从句,谓语动词用should 加动词原形,should 可省略。
It is 可用的词有三类 that (should)do
suggested, ordered, required, proposed, demanded, requested, insisted等
important, necessary, natural, imperative, strange等
a pity, a shame, no wonder等
2)在宾语从句中的应用
在表示命令、建议、要求等一类动词后面的从句中,像order, suggest, propose, require, demand, request, insist, command, insist + (should) do等。例如:
 I suggest that we (should) hold a meeting next week. 我建议下周召开个会议。
  He insisted that he (should ) be sent there.他要求被派到那儿去。
  注意:如suggest, insist不表示"建议" 或"坚持要某人做某事时",即它们用于其本意"暗示、表明"、"坚持认为"时,宾语从句用陈述语气。
3)在表语从句,同位语从句中的应用
suggestion, proposal, idea, plan, order, advice等名词后面的表语从句、同位语从句中要用虚拟语气,即(should)+动词原形。
wish的用法
1)wish后面的从句,表示与事实相反的情况,或表示将来不太可能实现的愿望。其宾语从句的动词形式为:
主句 从句
从句动作先于主句动词动作(be的过去式为 were) 现在时 过去时
从句动作与主句动作同时发生(had + 过去分词) 过去时 过去完成时
将来不大可能实现的愿望 将来时 would/could +动词原形
8. 比较if only与only if
  only if表示"只有";if only则表示"如果……就好了"。If only也可用于陈述语气。
9.It is (high) time that
  It is (high) time that 后面的从句谓语动词要用过去式或用should加动词原形,但should不可省略。
10.need "不必做"和"本不必做"
  didn't need to do表示过去不必做某事, 事实上也没做。
  needn't have done表示过去不必做某事, 但事实上做了。
相关练习题
1.(B)The volleyball match will be put off if it ___. 
A. will rain 
B. rains 
C. rained 
D. is rained
 考点:真实条件句主句为将来时,从句用一般现在时。
注意:
1)在真实条件句中,主句不能用be going to表示将来,该用shall, will.
  (错) If you leave now, you are never going to regret it.
  (对) If you leave now, you will never regret it.
2)表示真理时,主句谓语动词不用shall (will) +动词原形,而直接用一般现在时的动词形式
1.(C)_____ to do the work, I should do it some other day.
A. If were I  
B. I were 
C. Were I 
D. Was I
考点:在虚拟条件状语中如果有were, should, had这三个词,通常将if省略,主语提前, 变成 were, should, had +主语的形式。但要注意,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。如我们可说 Were I not to do, 而不能说 Weren't I to do。
2.(D)There was plenty of time. She ___.
A. mustn't have hurried 
B. couldn't have hurried 
 C. must not hurry 
D. needn't have hurried
  考点:needn't have done. 意为"本不必",即已经做了某事,而时实际上不必要。
  Mustn't have done 用法不正确,对过去发生的事情进行否定性推断应为couldn't have done, "不可能已经"。 must not do 不可以(用于一般现在时)。

虚拟语气经典习题
1. If I had had enough time, I      my work.  
 A. would finish    
B. must have finished
 C. would have finished  
D. had finished
2. Ten minutes earlier, they      the plane.  
A. will catch 
B. would catch 
C. would have caught 
D. will have caught
3. Mr. Green requires that the students     a composition every other week.                 
A. write  
B. written  
C. would write  
D. will write
4. Had he studied hard, he    the exam.     
A. would pass 
B. could pass 
C. had passed 
D. would have passed
5. I wish I    what is happening there in his room. 
A. know  
B. known  
C. knew  
D. should know
6. It is important that you      sports every day. 
A. have  
B. would have  
C. must have  
D. will have
7. If there were no water in the world, everything   . 
A. will die 
B. would die 
C. would have died 
D. would have been dead
8. What was going to happen ,I would never have left her alone.                     
A. Had I known  
B. If I know 
C. If I knew   
D. If had I known
9. He ordered that the work
A. should finish 
B. finished 
C. would be finished  
D. be finished      . 
10. — Shall we go to the movie tonight?
— No, I'd rather      at home with our baby. You'd better not leave it to the babysitter at night.
 A. you stayed  
B. you stay  
C. stayed  
D. stay
11 .    in your position, I would help him.  
A. Was I   
B. Were I   
C. If I am   
D. If I had been
12. I     , but I was stopped by the heavy rain.   
A. mean to come 
B. meant to come 
C. had meant to come 
D. meant coming
13. Mrs. Black insists      in that old hotel.  
A. not to stay 
B. not staying 
C. staying not  
D. that he not stay
14. If you had spoken clearly, you would     .   
A. understand it 
B. have understood
C. be understood
D. have been understood
15. If you      that late movie last night, you wouldn't be so sleepy.                        
A. haven't watched 
B. hadn't watched  
C. didn't watch
D. wouldn't have watched
16.The foreign friend speaks Chinese so well as if he    a Chinese.                         A. is  
B. be  
C. should be  
D. were
17. — If he   , he   that food.   
— Luckily he was sent to the hospital immediately.
A. was warned; would not take 
B. would be warned; had not take 
C. had been warned; would not have taken 
D. would have been warned; had not taken
18. Without electronic computers, much of today's advanced technology    achieved.               
A. will not be 
B. would not be  
C. would not have been 
D. cannot have been
19.There was plenty of time. She ___.
A. mustn’t have hurried 
B. couldn’t have hurried  
C. must not hurry 
D. needn’t have hurried
 答案D。needn’t have done. 意为"本不必",即已经做了某事,而时实际上不必要。
 Mustn’t have done 用法不正确,对过去发生的事情进行否定性推断应为couldn’t have done, "不可能已经"。 must not do 不可以(用于一般现在时)。
20. We had hoped that he ____ longer.
A. stays   
B. have stayed   
C.stayed   
D. would stay
  解析:该题正确答案为D。had hoped表示"本希望",同样用法的动词还有think, expect等,后面的句子需用虚拟语气
21."Mary wants to see you today".
 "I would rather she ____ tomorrow than today."
 A.comes   
B.came   
C.should come   
D.will come
 解析:该题正确答案为B。would rather后面的从句需用虚拟语气,用动词过去时表示。
22.Had she been older, she ____ it better.
A.had done   
B.might have done   
C.might do   
D.would do
解析:Had she been older = If she had been old.故该题正确答案为B。

A.should finish 
B.finished 
C.would be finished  
D.be finished
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第1个回答  2011-07-01
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。下面分别介绍虚拟语气在各种句式中的用法。

1. 虚拟语气用于条件状语从句

注意:主句中的should通常用于第一人称,would可用于任何人称,同时也可根据意思用情态动词could, might等代替should, would。

1)表示与现在事实相反:

If I were you, I should stay at home.

If the peasants could farm the land themselves, food production would be much higher.

If fewer cash crops were grown, more food could be produced and there would be less or no starvation.

2)表示与过去事实相反:

If you had come yesterday, you would have met him.

If the hurricane had happened during the daytime, there would have been many deaths.

3)表示与将来事实相反:If you came tomorrow, we would have the meeting.

If it were to/should rain tomorrow, the meeting would be put off.

If it should rain, the crops would be saved.

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 followed the doctor's advice, you would be quite all right now. (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从句省略if,用倒装句式"were, had, should+主语"。例如: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.②用介词短语代替条件状语从句。例如:Without air, there would be no living things. I would not have succeeded but for your help.

2.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式;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)would + have + 过去分词"。例如:

I wish we could go to the seaside today.

I wish you told me earlier.

We wish we had arrived there two hours earlier.

2)虚拟语气在动词arrange, command, demand, desire, insist, order, propose, request, require, suggest 等后面的宾语从句中,用"(should)+动词原形"。例如:

I suggested that the meeting (should) be put off.

The doctor ordered that she (should) stay in bed for a few days.

They demanded that the black people should be treated as well as white people.

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(应该)"解时,宾语从句才用虚拟语气。例如:

Mike insisted that he had never stolen anything.

I insisted that you give me my money back.

3.虚拟语气用于表语从句、同位语从句做advice, idea, order, demand, plan, proposal, suggestion, request 等名词的表语从句和同位语从句,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 he (should) do exercises first.

4.虚拟语气用于以as if(as though)引导的表语从句或状语从句

如果从句表示与现在事实相反,谓语动词用一般过去时;表示与过去事实相反,谓语动词用"had+过去分词";表示与将来事实相反,谓语动词用"would(might, could )+动词原形"。例如:

He looked at me as if I were mad.

He speaks English so fluently as if he had studied English in England.

It looks as if it might rain.

但as if(as though)后的从句也常用陈述语气,这是因为从句中的情况往往是可能发生的或可能被设想为真实的。例如:

It looks as if our side is going to win.

5.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用"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, desirable, advisable, 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示惊奇,就可用虚拟语气。反之,如果不表示惊奇,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.本回答被提问者采纳
第2个回答  2011-07-03
那个老师是对你们 好 你们要好好学啊