学文网英语四级高级语法讲解：虚拟语气
虚拟语气是说话者用来表示假设，或难以实现的情况，而非客观存在的事实，所陈述的是一个条件，不一定是事实，甚至完全与事实相反。下面是整理的英语四级高级语法讲解：虚拟语气，欢迎大家阅读学习。
1.if 引导的虚拟语气
2.倒装形式
Were I you(=if I were you),I would get up early in the morning.
Had you arrived at the station ten minutes earlier yesterday(=If you had arrived…),you could have caught the train.
Should it rain(=If it should rain),the crops would be saved.
It is time that ...
Would rather that.....
(1)I would rather he came tomorrow than today.
(2)John would rather that she had not gone to the party yesterday evening.
(3)I would rather everything hadn t happened in the past.
“It is(was)+形容词(或过去分词)+that……”结构中的虚拟语气
1.It is necessary that we(should 可省略,下同)have a walk now.
2.It was necessary that we(should) make everything ready ahead of time.
3.It is required that nobody(should) smoke here.
4.It is important that every pupil(should) be able to understand the rule of school.
练习
1.He’ll be busy this afternoon.If he ___ free,he ___ to the cinema with you.
A.were to be; might go B.am going to be; will go
C.will be; might have gone D.is; will go
2.When Edison died,it was proposed that the American people _____ all power in their homes,streets,and factories for several minutes in honor of this great man.
A.turn off B.turned off
C.would turn off D.had turned off
3.Had I known her name,_____.
A.or does she know mine? B.and where does she live?
C.I would have invited her to lunch D.she would be beautiful
4.I’d rather you ______ by train,because I cant bear the idea of your being in an airplane in such bad weather.
A.would go B.should go
C.went D.had gone
5.The victim ________(本来会有机会活下来) if he had been taken to hospital in time.
would have a chance to survive(06.12翻译)
6.The professor required that ________(我们交研究报告)。
we hand in our research report(s)(06.6翻译)
7.If Sept.11 had never happened,the airport workers would not have been arrested and could have gone on quietly living in America,probably indefinitely.(06.6阅读)
8.W: What would you do if you were in my place?
M: If Paul were my son,I’d just not worry.Now that his teacher is giving him extra help and he is working hard himself,he’s sure to do well in the next exam.
Q: What’s the man’s suggestion to the woman?
13.A) Teaching her son by herself.C) Asking the teacher for extra help.
B) Having confidence in her son.D) Telling her son not to worry.(07.12)
1.You’d better take a sweater with you ________________(以防天气变冷)
in case it(should) turn cold.(08.12)
10.If she had returned an hour earlier,Mary(就不会被大雨淋湿了).
.wouldn’t have been caught by the rain
11.You would not have failed if you __________________________(按照我的指令去做).
had followed my instructions/orders
虚拟语气用于定语从句中
在It is(high,about)time(that)…句型中，that引导的定语从句中的谓语常用一般过去时来构成虚拟语气。
例：It’s about time that we put an end to this controversy.现在该是我们停止这场争论的时候了。例：It is time we went to bed.
我们该去睡觉了。
虚拟语气用于if only 引导的从句中
在if only引导的从句中，谓语动词须采用虚拟语气，其用法与wish后宾语从句的用法基本相同，表示“但愿”，“要是…就好了”的意思。例：If only I knew what you wanted.要是我知道你需要什么就好了。
例：If only he had arrived in time,he would not have been punished.
虚拟条件句中虚拟语气的运用：
虚拟条件句从时间上又分为与现在事实相反，与过去事实相反，与将来事实可能相反三种情况。表示与现在事实相反的，if从句用过去式，主句用would（或could ,should ,might）加原形动词。与过去事实相反的，if从句用过去完成时，主句用would（或could ,should ,might）+have done结构。与将来事实可能相反的，if 从句用should（或were to ）加动词原形，主句用would加动词原形。
1、If a better material _____,the strength of the part 高中语文 would have been increased.
A.had been used
B.had been using
C.being used
D.using
（根据前面的讲解，正确答案为A。）
2、Had the weather been good,the children _____ out for a walk.
A.had gone
B.could have gone
C.would go
D.went
（答案：B。与过去的事实相反。当if从句中含有were,had,should这三个词时，if可以省略，主谓倒装。）
某些动词后的宾语从句以及某些名词后的表语或同位语从句中虚拟语气的运用，这些动词或名词包括：
suggest（suggestion）,propose（proposal）,advise（advice）demand,insist,order,request,require,recommend,desire,ask,decide等。在这些从句中，谓语形式为should加动词原形，should可以省略。
例：The general’s command was that the soldiers _____ their fort and carry out more important task.
A.would leave
B.leave
C.left
D.have left
（答案：B）
在It is desired（或desirable）,It is important等结构后面的主语从句中，动词用原形或should+原形动词。这些结构有：
“It is suggested”,“It is requested”,“It was ordered”,“It is necessary”,“It is essential”,“It is vital”,“It is urgent”,“ It is impossible”,“It is preferable”,“It is advisable”,“It was proposed”等。
例：It’s desired that she _____ to teach us at least twice a week.
Aes
B.will com
Ce
D.may come
（答案：C）
would rather,as if/though 以及wish后边that从句中虚拟语气的运用。
1、I am too busy these days.I would rather all of you _____ next month for a dinner.
Ae
B.would come
C.came
D.have come
（答案：C。would rather 后面的从句中，动词用过去式。）
2、He talks as if he _____ everything in the world.
A.knows
B.knew
C.had known
D.would have know
（正确答案为B。在as if/though后边的方式状语从句中，表示与现在事实相反或对现在的情况有所怀疑，动词用过去式；如果表示的是中的过去的动作，用过去完成时。本句表示对现在的情况有所怀疑。）
3、You look as if you had seen a ghost.
（此句中as if 后边是说话人想象中的动作，所以用过去完成时。）
4、I wish I knew his address.
（在wish后边的从句中，如果指现在或将来的愿望，动词用过去式。这句话告诉我们说话人并不知道他的地址。）
5、Peter wishes that he _____ law instead of literature when he was in college。
A.could study
B.studied
C.had studied
D.would study
（答案为C。表示过去没有实现的愿望，动词用过去完成时。）
在It is（high） time后边的that从句中，动词用过去式，表示该做某事了。
例：Don’t you think it is time you _____ smoking?
A.give up
B.gave up
C.would give up
D.should give up
（答案为B。）
虚拟语气用在定语从句中
It is time(that)…句型中的定语从句里的谓语动词常用虚拟浯气表示将来，动词形式用动词的过去式：意思是"该干某件事了，时间已经有些晚了"。如：
It is time we left.我们该走了。
It is time we went to bed.我们该睡觉了：
It is time we summed up our results.我们该总结我们的成绩了。
虚拟语气用在简单句中
下面是虚拟语气用在简单句中较常见的两种情况，皆表祝愿。如：
1)动词原形1ive用在Long live…中。如：
Long live the Communist Party of China! 中国***万岁!
Long live the people! 人民万岁!
(1ive在此也是虚拟语气的一种动词形式，不可改为lives)
2)May用在句子开头(多用在正式的文体中)。如：
May good luck be yours.祝你顺利。
May you be happy.祝你快乐。
May you do even better! 祝你取得更大成就!
用以表示虚拟条件的虚拟语气
1.用if条件从句表示的虚拟条件，是虚拟条件最普通的方式。
①虚拟现在时表示与现在事实相反的假设，其if 从句的谓语形式用动词的过去式(be 一般用were)，主句用would/ should/ could/ might +动词原形，例如：If I were in your position I would marry her.
②虚拟过去时是表示与过去事实相反的假设，if 从句的谓语形式用过去完成时即had＋过去分词，主句用would/should/could/might +have +过去分词，例如：If it had not rained so hard yesterday we could have played tennis.
③大多数的虚拟条件句属于上面三种情况的一种，但并不排除存在条件和后果中，一个和现在情况相反，另一个和过去情况相反，例如：If you had followed what the doctor said,you would not have been so painful now.这个句子在高中出现频率颇高。
④但是，如果后果用了虚拟语气，而条件却用陈述语气，这种用法是错的。
2.除了表示虚假条件外，if从句还可以表示对将来的推测，由于是将来还没有发生的，所以谈不上是真实的还是虚假的，只能说这个事情发生的可能性有多大。一般情况下，可以用陈述语气的if从句来表示对一个未来事实的推测，这个事实是完全可能发生的。If从句的谓语形式用一般过去式或用were to/should +动词原形，主句用would/should /could/ might +动词原形，例如：Jean doesnt want to work right away because she thinks that if she were to get a job she probably wouldnt be able to see her friends very often.
3.有时可以把含有助动词、情态动词、be或have的虚拟条件句中的连词if 省去，而将had,should,were 等词提到主语之前，即用倒装结构,这时候，如果出现not等否定词，否定词需放在主语后面。这种结构在口语中很少使用，但频频出现在各类考试中出现，例如：If it had not rained so hard yesterday we could have played tennis.→Had it not rained so hard yesterday,we could have played tennis.
4.大多数的虚拟条件通过上面所讲的两种方法表达，但在个别句子中也可以通过介词without和介词短语but for表达，副词otherwise等表达出来。例如：We didnt know his telephone number; otherwise we would have telephoned him.值得注意的是，包含but for的句子，谓语动词必定要用虚拟形式，但包含without等短语的句子，谓语动词未必一定要用虚拟语气。
5.有时虚拟条件不是明确地表达出来，而在蕴含在用but引导的从句里，于是便出现了有谓语动词是虚拟语气的主句加上谓语动词是陈述语气的but从句构成的并列复合句，例如I would have hung you but the telephone was out of order.在这样的句子里，如果主句没有用虚拟语气，或者从句用了虚拟语气，都是错的。
用在宾语从句中的虚拟语气
1.在表示愿望的动词wish后的宾语从句中，需用虚拟语气。（wish后的that 常省略），根据主句时态，从句谓语时态相应退后一位，例如：How she wished his family could go with him.
2.在具有愿望、请求、建议、命令等主观意愿的动词(desire,demand,advice,insist,require,suggest,propose,order,recommend,decide…) 后的宾语从句中需用虚拟语气。谓语动词用(should) +动词原形。值得注意的是，如果宾语从句的动词是否定的，否定词not的位置应在动词之前，而不是动词之后。例如：The head nurse insisted that the patient not be move.另外，如suggest表达“暗示”，insist表示“坚持某种说法”时，后面的从句不用虚拟语气，例如：Her pale face suggests that she is ill.或He insisted that he did not kill the boy.
除此之外，上述动词也要求用虚拟式
①在It is+上述动词的过去分词，其后所跟的主语从句中，如It is suggested that pupils wear school uniforms.
②在上述动词相应的名词形式作主语+连系动词，其后的表语从句中，例如His suggestion was that classed be re-scheduled.
③在对上述动词相应的名词进行解释的同位语从句中，如：The workers raised the demand that their pay be increased to cope with the inflation.
3.would（had）rather,would sooner也用来表达主观愿望，它们之后的宾语从句中需用虚拟语气。谓语动词用过去式表示现在或将来，用过去完成式表示与过去事实相反，例如：I would rather he went right now.
其他形式的虚拟语气
1.it is +necessary等形容词后，that主语从句中虚拟形式使用，这类形容词包括necessary,important,essential,imperative,urgent,preferable,vital,advisable等，例如It is necessary that you listen to the teacher carefully.或者It is essential that you be able to pronounce every single word correctly.
2.在Its(high/about) time 之后的定语从句中需用虚拟语气。谓语动词用过去式，例如It is high time that you went to school
3.虚拟语气在as if/as though 引导的方式状语从句中的应用（谓语动词形式与wish后的宾语从句基本相同）表示与现在事实相反或对现在情况有怀疑，谓语动词用过去式。例如：He felt as if he alone were responsible for what had happened.表示过去想象中的动作或情况，谓语动词用过去完成式。
4.在lest引导的状语从句中，谓语动词多用虚拟语气，(should )+动词原形。例如： The mad man was put in the soft-padded cell lest he injure himself.
5.在if only引起的感叹句中需用虚拟语气。谓语动词用过去式或过去完成式。例如： Look at the terrible situation I am in! if only I had followed your advice.
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