英语中虚拟语气有什么用法？举一下例子，谢谢！

Answer 1

虚拟语气(Subjunctive Mood)这一语法项目是各类英语考试中心测试的重点之一。虚拟语气是一种特殊的动词形式，用来表示说话人所说的话并不是事实，而是一种假设、愿望、怀疑或推测。
Ⅰ用以表示虚拟条件的虚拟语气
⒈ 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。
⒉ 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 doesn't want to work right away because she thinks that if she were to get a job she probably wouldn't be able to see her friends very often.（1996年1月四级第44题）
⒊ 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.
⒋ 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 didn't know his telephone number; otherwise we would have telephoned him.（1995年6月四级第46题）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。
⒌ 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。
Ⅱ用在宾语从句中的虚拟语气
⒈ 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.
⒉ 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.
⒊ 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.
Ⅲ其他形式的虚拟语气
⒈ 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.
⒉ 在It's (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
⒊ 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。
⒋ 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.（1998年1月四级第38题）
⒌ 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.

Answer 2

动词的语气——虚拟语气(The Subjunctive Mood)
一、语气的定义和种类
l、语气：语气是动词的一种形式，它表示说话人对某一行为或事情的看法和态度。
2、语气的种类：
(1)陈述语气: 表示动作或状态是现实的、确定的或符合事实的，用于陈述句、疑问句和某些感叹句。如：We are not ready. 我们没准备好。What a fine day it is!多好的天气啊!
(2)祈使语气: 表示说话人的建议、请求、邀请、命令等。如: Open the door, please。请打开门。
(3)虚拟语气: 表示动作或状态不是客观存在的事实，而是说话人的主观愿望、假设或推测等。如: If I were you, I should study English. 如果我是你，我就学英语了。May you succeed! 祝您成功！
二、虚拟语气在条件从句中的用法
条件句有两类，一类是真实条件句，一类是虚拟条件句。如果假设的情况是有可能发生的，就是真实条件句。在这种真实条件句中的谓语用陈述语气。如: If it doesn’t rain tomorrow, we will go to the park. 如果明天不下雨，我们就去公园。
如果假设的情况是过去或现在都不存在的，或将来不大可能发生的，则是虚拟条件句。如: If he had seen you yesterday, he would have asked you about it. 如果他昨天见到你，他会问你这件事的。(事实上他昨天没见到你，因此也未能问你这件事。)
在含有虚拟条件句的复合句中，主句和从句的谓语都要用虚拟语气。现将虚拟条件从句和主句的动词形式列表如下:

与现在事实相反: 从句: 动词的过去式（be的过去式一般用were）
主句:would/ should/ could/ might + 动词原形
与过去事实相反 : 从句 :had + 过去分词
主句 :would/ should/ could/ might + have + 过去分词
与将来事实相反 : 从句:动词过去式，should + 动词原形，
主句 :were to + 动词原形 would/ should/ could/ might + 动词原形
注: 主句中的should只用于I、we，但在美国英语中，should常被would代替；从句中的should可用于各种人称。
l、表示与现在事实相反的假设和结果。如: If my brother were here, everything would be all right. 要是我哥哥在这儿 ，一切都没问题了。
2、表示与过去事实相反的假设和结果。如: If you had taken my advice，you wouldn't (couldn’t) have failed in the exam. 如果你按照我的建议去做，你一定不会(不可能)考试不及格。
3、表示与将来事实可能相反的假设和结果。如: If it were Sunday tomorrow, I should (would，could，might) go to see my grandmother. 如果明天是星期天，我就 (可能)去看望我奶 奶。If it were to snow this evening, they would not go out. 如果今晚下雪，他们将不出去了。
4、有时条件从句中的动作和主句中的动作发生的时间不一致（表示错综时间的虚拟语气），这时动词的形式要根据它所表示的时间加以调整。例如: If you had listened to the doctor, you would be all right now. 如果你当初听了医生的话，身体现在就好了。(从句动作指过去，主句动作指现在)
5、虚拟条件句可以转换成下列形式:
(l)省略连词if。在书面语中，如果虚拟条件从句中有were，had 或 should，可以把if省略，把这几个词放到主语之前，构成主谓倒装。例如: Should he come (If he should come), tell him to ring me up. 他要是来了，让他给我打个电话。Were I you (If I were you), I would not do it. 我要是你，就不做这事。
(2)用介词短语代替条件状语从句。有时假设的情况并不用条件从句表示出来，而是通过介词短语来表示。如: Without air (If there were not air), there would be no living things. 如果没有空气的话，就不会有生物了。But for your help (If it hadn’t been for your help) I couldn’t have done it. 要是没有你的帮助，我就不可能完成这件事。
假设的情况有时可以通过上下文或其他方式表现出来。如: I was busy that day. Otherwise I would have gone there with them. (If I hadn’t been busy that day, I would have gone there with them.) 我那天很忙，否则，我就和他们一起去那儿了。(如果我那天不忙的话，我就……)；I would have finished the work, but I have been ill. (If I hadn’t been ill, I would have finished the work.) 我本来该完成这项工作的，但我生病了。(如果我没生病的话，我就会完成……)
6、省去条件从句或主句：表示虚拟语气的主句或从句有时可以省略，但其含义仍可以推知。
(1)省去条件从句。如: You could have washed your clothes yourself. 你本可以自已洗衣服的。省去了"If you had wanted to")(事实是:你自己没洗衣服，因为你不想洗。)
(2)省去主句(常用以表示愿望)。如: If my grandmother were with me! 如果我的祖母与我在一起多好啊!(事实是:祖母已不在世。)；If only she had not left! 如果她没走就好了!(事实是:她已经走了。)

Answer 3

在条件句中的应用
条件句可分为两类，一类为真实条件句，一类为非真实条件句。非真实条件句表示的是假设的或实际可能性不大的情况，故采用虚拟语气。
1.真实条件句
真实条件句用于陈述语气，假设的情况可能发生，其中 if 是如果的意思。
时态关系
句型：条件从句 主句
一般现在时shall/will + 动词原形
If he comes, he will bring his violin.
典型例题
The volleyball match will be put off if it ___.
A. will rain B. rains C. rained D. is rained
答案B。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，主句谓语动词便不用shall (will) +动词原形，而直接用一般现在时的动词形式。
2.非真实条件句
1）时态：可以表示过去，现在和将来的情况。它的基本特点是时态退后。
a. 同现在事实相反的假设。
句型 ： 条件从句 主句
一般过去时 should( would) +动词原形
If they were here, they would help you.
b. 表示于过去事实相反的假设。
句型： 条件从句 主句
过去完成时 should(would) have+ 过去分词
If she had worked harder, she would have succeeded.
The rice would not have been burnt if you had been more careful.
If my lawyer had been here last Saturday, he would have prevented me from going.
If he had come yesterday, I should / would have told him about it.
含义：He did not come yesterday, so I did not tell him about it.
If he had not been ill and missed many classes, he would have made greater progress.
含义： He was ill and missed many lessons, so he did not make greater progress.
c. 表示对将来的假想
句型： 条件从句 主句
一般过去时 should+ 动词原形
were+ 不定式 would + 动词原形
should+ 动词原形
If you succeeded, everything would be all right.
If you should succeed, everything would be all right.
If you were to succeed, everything would be all right.
3.混合条件句
主句与从句的动作发生在不同的时间，这时主，从句谓语动词的虚拟语气形式因时间不同而不同，这叫做混合条件句。
If you had asked him yesterday, you would know what to do now.
（从句与过去事实相反，主句与现在事实相反。）
If it had rained last night (过去), it would be very cold today (现在).
4.虚拟条件句的倒装
虚拟条件句的从句部分如果含有were, should, 或had, 可将if省略，再把were, should或had 移到从句句首，实行倒装。
Were they here now, they could help us.
=If they were here now, they could help us.
Had you come earlier, you would have met him
=If you had come earlier, you would have met him.
Should it rain, the crops would be saved.
=Were it to rain, the crops would be saved.
注意：
在虚拟语气的从句中，动词'be'的过去时态一律用"were"，不用was， 即在从句中be用were代替。
If I were you, I would go to look for him.
如果我是你，就会去找他。
If he were here, everything would be all right.
如果他在这儿，一切都会好的。
典型例题
_____ to do the work, I should do it some other day.
A. If were IB. I were C. Were I D. Was I
答案C. 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.
5特殊的虚拟语气词：should
1） It is demanded / necessary / a pity + that…结构中的主语从句的谓语动词要用should 加动词原形， should 可省略。
句型：
(1)suggested
It is (2)important that…+ (should) do
(3) a pity
(1)suggested, ordered, proposed, required, demanded, requested, insisted； + (should) do
(2)important, necessary, natural, strange
a pity, a shame, no wonder
例：It is suggested that we (should) hold a meeting next week.
It is necessary that he (should) come to our meeting tomorrow.
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。
order, suggest, propose, require, demand, request, insist, command, insist + (should) do
I suggest that we (should) hold a meeting next week.
He insisted that he (should ) be sent there.
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。
The guard at gate insisted that everybody obey the rules.
判断改错:
（错） You pale face suggests that you (should) be ill.
(对) Your pale face suggests that you are ill.
(错) I insisted that you ( should) be wrong.
(对) I insisted that you were wrong.
3）在表语从句，同位语从句中的应用
在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。
My idea is that we (should) get more people to attend the conference.
I make a proposal that we (should) hold a meeting next week.
6.wish的用法
1）用于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：
真实状况 wish后
从句动作先于主句动词动作 过去时 过去完成时
（be的过去式为 were）
从句动作与主句动作同时发生 现在时 过去时
（had + 过去分词）
将来不大可能实现的愿望 将来时 would/could +
动词原形
I wish I were as tall as you. 我希望和你一样高。
He wished he hadn't said that. 他希望他没讲那样的话。
I wish it would rain tomorrow. 我希望明天下雨就好了。
2）Wish to do表达法。
Wish sb / sth to do
I wish to see the manager. = I want to see the manager.
I wish the manager to be informed at once. (= I want the manager to be informed at once.)
7.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。
I wake up only if the alarm clock rings. 只有闹钟响了，我才会醒。
If only the alarm clock had rung. 当时闹钟响了，就好了。
If only he comes early. 但愿他早点回来。
8.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。
It is time that the children went to bed.
It is high time that the children should go to bed.
9 need "不必做"和"本不该做"
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。
John went to the station with the car to meet Mary, so she didn't need to walk back home. 约翰开车去车站接玛丽，所以她不必步行回家了。
John went to the station with the car to meet Mary, so she needn't have walked back home. 约翰开车去车站接玛丽，所以她本不必步行回家了。 (Mary步行回家，没有遇上John的车。)
典型例题
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）。
语气是一种动词形式，用以表示说话者的意图或态度。虚拟语气表示说话者的主观愿望、假想和建议等，所说的话有的与现在事实相反，或与过去事实相反，或与将来事实相反或与将来事实可能相反。所以虚拟语气总是与假设条件句用在一起。除了if条件句外，还有几种常用的条件句，短语也可表示条件。此外，上下文也能创造虚拟的语言环境。但有时条件从句与结果主句可能发生时间不一致，有时虚拟语气会出现倒装情况。除了与条件句在一起使用的主句用虚拟语气外，有些宾语从句或表语从句也有用虚拟语气的情况。

Answer 4

If I was you ,I would not ask this question.