虚拟语气绝对是令很多人感到头痛的一个语法点。这是我从网上和一些语法书上收集整理而成的一份学习资料，希望对你有用。如果觉得好，支持一下，便是给我的最大鼓励。
虚拟语气
第一部分：语气的定义和种类
1 语气(mood)
语气是动词的一种形式，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
⑴、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：
①There are two sides to every question.每个问题都有两个方面。
②Were you busy all day yesterday?昨天一整天你都很忙吗？
③How good a teacher she is!她是多好的一位老师啊！
⑵、祈使语气：表示说话人对对方的请求或命令。如：
①Never be late again!再也不要迟到了。
②Don’t forget to turn off the light.别忘了关灯。
⑶、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：
①If I were a bird, I could fly in the air.如果我是一只小鸟，我就能在空中飞行。
②I wish I could pass the examination.我希望我能通过考试。
③May you succeed!祝您成功！
虚拟语气在语法里算得上是个难点。让我们就从最简单的开始吧。
第二部分：简单句中的虚拟语气
一、情态动词的过去式用于现在时态时，表示说话人的谦虚、客气、有礼貌、或委婉的语气，常用于日常会话中。如：
⑴.Would you be kind enough to show me the way to the post
office?请你告诉我去邮局的路好吗？
⑵.It would be better for you not to stay up too late.你最好别熬夜到很晚。
二、表祝愿。
1、常用“may+动词原形”表示祝愿，但愿，此时may须置于句首（多用于正式文体中）。
⑴、May good luck be yours!祝你好运！
⑵、May you be happy!祝你快乐！
⑶、May you do even better!祝你取得更大成就！
⑷、May you have a good time. 祝愿你玩的痛快。
⑸、May the friendship between us last long. 祝愿我们的友情天长地久。
⑹、May you be happy. (注意那个be ) 祝你幸福。
2、用动词原形。例如：
(1).Long live the people! 人民万岁！
(2).“God bless you,”said the priest.牧师说：“愿上帝保佑你！”
(3).Have a good journey! 祝愿你旅途愉快！
三、表示强烈愿望。（该类型虚拟语气谓语仅用动词原形，第三人称单数也不加“s”）
(1).God save me．
(2).Heaven help us．
四、表命令
1.命令虚拟语气只能用在第二人称(you)，而且通常省略主语(也就是you)。
2.句子尾通常加上感叹号：！
3.虚拟语气动词用一般现在时态(Simple Present)，如：work, be , go
4.否定形式的命令语气，可用助动词do，加上not。
(1). Work !
(2). Work harder !
(3). Be more alert ! (虚拟语气动词Be)
(4). You go out !
(5). Do not work so hard. (do not 表示否定的虚拟语气)
(6). Don't be afraid. (口语中常用don't 代替do not)
五、在一些习惯表达中。如：
(1).You’d better set off now.你最好现在就出发。
(2).I’d rather not tell you the secret.我情愿不告诉你这个秘密。
第一讲虚拟语气
虚拟语气是英语动词的一种特殊形式，表示说话人主观上所说的话并不是事实，而是一种假设、愿望、建议、请求、命令、空想、猜测，必要性和可能性等。虚拟语气是英语学习中一个难点，也是大学英语测试中的重要的语法考点之一。测试内容涉及到虚拟语气的方方面面------从在含非真实条件的主从句中的应用，到在各种从句(主语从句、宾语从句、表语从句、同位语从句、状语从句、定语从句)中的应用。由于虚拟语气表达的是一种与事实相反的行为状态，其谓语动词的变化不同于陈述语气，这也是大家感到困惑和容易出错的地方。解此类试题时，关键是要迅速发现解题信息词，确定虚拟语气类型，然后按各类虚拟语气的特定表达方式，或根据结构或题句中的其他暗示，确定动词的形式。
(一)虚拟条件句
一、虚拟语气在非真实条件句中的应用
非真实条件句表示不大可能或不可能发生或实现的的假设，句中的条件从句与结果主句皆须用虚拟语气。其虚拟语气的时态可用以下内容表示：
1、虚拟现在时(与现在事实相反),从句谓语形式用动词的过去式(be一般用were)，主句谓语形式Should(would,could,might)+动词原形
2、虚拟过去时(与过去事实相反)，从句谓语形式用Had+过去分词，主句谓形式Should(would,could,might)+have+过去分词
3、虚拟将来时(与将来事实相反)，从句谓形式用动词的一般过去式，或were to +动词原形或should+动词原形，主句谓语形式 hould(would,could,might)动词原形
练习：
1：If the whole operation______beforehand, a great deal of time and money would have been lost.
A )was not planned
B)has not been planned
C)had not been planned
D)were not planned
2、Jean doesn't want to work right away because she thinks that if she _____a job she probably wouldn't be able to see her friends very often.
A)has to get
B)were to get
C)had got
D)could have got
解析：1、答案C。由主句的谓语动词would have been lost 可以判断，本题考查的是表示与过去事实相反的虚拟语气的用法，if 引导的从句须用过去完成时，故C项为正确答案。本句题意是：如果整个手术不提前安排的话，那就要浪费大量的时间和金钱。
2、答案B。because引导的原因状语从句中有一个虚拟结构，if 条件从句谓语动词的时态应与wouldn’t be able to 对应，表示与将来事实相反的虚拟，条件从句的谓语应用should或were to +动词原形，因此B项正确。本题句意是：吉恩并不想马上去上班，因为好考虑到一旦上班，她很可能不能经常见到她的朋友们。
二、错综时间虚拟语气
在表示虚拟语气的句子中，条件从句表示的的动作与主句表示的动作发生的时间并不一致，这时，谓语动词的形式要根据各自表示的时间来调整，这种现象叫作错综时间虚拟语气，也称作混合虚拟语气。
例：
If you had taken your medicine yesterday, you would be quite all right now.
如果你昨天吃了药的话，现在就已经痊愈了。(从句表示与过去事实相反的假设，主句则表示与现在事实相反。)
经典练习：
1、If I hadn’t stood under the ladder to catch you when you fell, you____now.
A) couldn’t have smiled
B) wouldn’t be smiling
C) didn’t smile
D) won’t smile
2、____for the timely investment from the general public, our company would not be so thriving as it is.
A) Had it not been
B) Were it not
C) Be it not
D) Should it not be
3、If he knew this, it____be by accident.
A) would have to
B) didn’t to
C) won’t have to
D) woud have had to
解析1、选B。从主句的时间状语now以及从句的谓语可知，本题为一错综时间虚拟语气，从句表示与过去事实相反的假设，主句则表示与现在情况相反，故B项为正确答案。
2、选A。根据本题句意逻辑，条件从句的行为发生在主句之前，须用过去时的虚拟语气形式，故A项为正确答案。同时，它是由把if省略，助动词提前而形成倒装。B、C、D三项均不合题意。本题句意是：要不是能及时从社会获得投资，我们公司也不会像现在这样繁荣了。
3、选D。由从句的谓语可知，本题为一错综时间虚拟语气，从句表示与现在事实相反的假设，主句则表示与过去事实相反的设想。故D项为正确答案。本句题意：假如他已知此事，那一定是偶然的。
三、省略连词if 采用倒装的非真实条件句
在书面语中，条件从句可以不用连词if, 而将谓语中的过去式were,had或should等移至主语之前，构成倒装。
例：Were you in my position, you would do the same.
假如你处在我的地位，你也会这样干的。
例：Had he come earlier, he would have met her.
要是他早点来的话，他就会见到她了。
四、虚拟语气在储蓄条件句中的应用
非真实条件句中的条件从句有时不表示出来，只暗含在短语或上下文中，这种句子叫做储蓄条件句。常见的有but,for ,without等引导的短语，以及or, or else, otherwise, but 等后面的分句。
例：But for your help we couldn’t have succeeded in the experiment.
如果没有你的帮助，我们的实验室是不会成功的。
例：We could have done better under more favourable conditions.
在更有利的条件下，我们能够做得更好些。
经典考点：
1、____right now, she would get there on Sunday.
A)Would she leave
B)If she leaves
C)Were she to leave
D)If she had left
2、____for my illness I would have lent him a helping hand.
A)Not being
B)Had it not been
C)Without being
D)Not having been
3、We didn’t know his telephone number, otherwise we ____him.
A)would have telephoned
B)must have telephoned
C)would telephone
D)had telephoned
4、A safety analysis____the target as a potential dandger Unfortunately, it was never done.
A)would identify
B)will identify
C)would have identified
D)will have identified
解析：
1、答案选C。从句子结构可知，本题是表示与将来事实相反的虚拟语气。主句的谓语是“should+动词原形”。同时，从句省略了连词if, 可以将were提前，构成倒装。只以C符合语法规则。本题意思：如果她马上动身的话，她可能在星期天到达那里。
2、选B。从句子结构可知，空缺处应填入表示与过去事实相反的虚拟条件从句，并且将连词if 省略。此时应把虚拟语气的谓语动词提前。符合语法规则的只有B项。
3、选A。本题中otherwise引出的是一种与事实相反的假设条件，后面的句子应用虚拟语气。前一分句暗示了一个过去的时间，所以用不着would have done的形式，相当于If we had known his telephone number, we would have telephoned him.
4、选C。根据unfortunately后面直接陈述一个过去的事实，可以推断出第一个句子里含有一种“应该做某事而没有做的”虚拟条件。C项用于表示与过去事实相反的虚拟语气，正合题意。B、D不是虚拟语气。
一、虚拟语气用于主语从句中
在It is (was)important (necessary, desirable, imperative, advisable, incredible, urgent, possible, essential, natural, preferable, insistent, crucial, better, best, ridiculous, vital) that…能及It is (was) a pity (shame, wonder, must, suggestion, proposal, requirement, request, desire, order, recommendation) that….,It is (was)desired (arranged, decided, ordered, proposed, requested, recommended, suggested, settled) that…等句型的主语从句中，其谓语用“should+动词原形(其中should可以省略)”来构成虚拟语气。
例：It is important that we (should)speak politely.
我们说话要有礼貌，这是很重要的。
例：It is essential that she these application forms be sent back as early as possible.
将这些申请表格尽快地反馈回来是很必要的。
二、 虚拟语气用于宾语从句中
当动词ask, arrange, beg, advise, command, deserve, direct,desire, demand,determine, move, prefer, propose, intend, request, require, suppose 等后面接宾语从句时，从句的谓语用”should+动词原形” 来表示虚拟语气。
例: The judge ordered that the prisoner(should) be remanded.
法官命令被告还押。
Mr.Chairman, I move that the money____for library books.
主席先生，我提议把那笔钱用来购买图书馆书籍。
经典练习：
1、It is vital that enough money____ to fund the project.
A)be collected
B)must be collected
C)is collected
D)can be collected
2、It is recommended that the project____until all the preparations have been made.
A)is not started
B)will not be started
C)is not to be started
D)not be started
3、The manager of the hotel requests that their guests____afeter 10:30 p.m.
A)couldn’t play loud music
B)don’t play loud music
C)shouldn’t play loud music
D)not to play loud music
解析：
1、选A)。本题中vital后的主语从句用“should+动词原形”的虚拟语气形式，省略了should，来构成从句的谓语，符合语法规则，为正确答案。
2、选D)。动词recommend表示“建议”，其后的宾语从句须用“should+动词原形”的虚拟语气形式，should可以省略。所以C为正确答案。
3、选C)。在本题中，动词request后的宾语从句用”should+动词原形”的虚拟语气形式，并且是否定形式。
一、 虚拟语气用于wish后的宾语从句中
动词wish后的宾语从句中，谓语动词须用虚拟语气，表示与事实相反或不大可能实现的愿望。通常有三种形式：
①对将来发生的事情表示祝愿或愿望时，宾语从句的谓语用：would(could, might)+动词原形。
例：I wish he would try again. 我希望他再试一次。
例：I wish I could be of some use. 我希望我能有点用处。
②表示与现在事实相反的愿望时，宾语从句的谓语用一般过去时或过去进行时。
例：I wish I wasn’t going to Paris.
例：I wish I knew how to program the new computer.
③对过去发生的事情表示遗憾或后悔时，宾语从句的谓语用“过去完成时或could/would have done”的形式。
例：I wish you had come to our New Year’s party.
二、虚拟语气用于would rather, would just as soon 后的宾语从句中。
would rather, would sooner, would as soon 和would just as soon等短语表示“但愿”、“宁愿”等意思，其后的宾语从句中的谓语要用虚拟语气，常用过去式或过去完成式表示与现在或过去事实相反。
例：I’d sooner she left the heavy end of the work to someone else.
经典练习：
1、Jean wishes that he_____that house last spring.
A)bought
B)had bought
C)buys
D)were to buy
2、I wish I ____longer this morning, but I had to get up and come to class.
A)could have slept
B)slept
C)might have slept
D)have slept
3、I’d just as soon you ____those important papers with you.
A)dose not take
B)not to take
C)had not taked
D)did not take
4、I’d rather you____make any comment on the issue for the time being.
A)don’t
B)wouldn’t
C)didn’t
D)shouldn’t
解析：
1、选B。主句的谓语动词是wish时，其宾语从句用虚拟语气，表示与事实相反或不大可能实现的愿望。从本题的时间状语last spring可知，表示的是过去的愿望。因此从句应用于过去完成时表示，所以选B。
2、选A。从句中时间this morning 可知，本题表示对过去发生的事情表示遗憾，宾语从句的谓语须用过去完成时或could have done形式来表示虚拟语气，所以A项为正确答案。
3、选D。would just as soon的宾语从句的谓语动词用过去时来表示虚拟语气，符合语法规则的只有D项。
4、选C。for the time being意为”目前”，表示现在的时间，因些would rather表示现在不可能实现的愿望，要求从句使用过去时来表示虚拟语气，其否定形式为“didn’t+动词原形”。所以C为正确答案。
一、虚拟语气用于表语从句及同位语从句中
当advise, decision, desire, demand, idea, order, motion, necessity, insistence, instrution, plan, preference, proposal, pray, recommendation, requirement, resolution, suggestion, understanding等名词后接接表语从句或同位语从句时，从句的谓语用“should+动词原形”的形式来构成虚拟语气。
例：The professor gave order that the test be finished before 7:30.
教授指示考试须在七点半以前结束。
例：The suggestion that the mayor present the prizes was accepted by everyone.
二、虚拟语气用于方式状语从句中
在as if, as though 引导的方式状语从句中，虚拟语气的形式是：用过去时表示与现在事实相反或或对现在情况有所怀疑；用过去完成时表示对过去事实的假设。
例：It seems as if it were spring.
现在好像是春天似的。
例：She appeared as if she had known nothing about it.
她看上去对此一无所知。
三、虚拟语气用于目的状语从句中
在lest, for fear that, in case 等引导的目的状语从句中，谓语动词用“should+动词原形”来构成虚拟语气；在so that, in order that 等引导的目的状语从句中，谓语动词除了用“should+动词原形”外，还可以用“might, could+动词原形”来构成虚拟语气。
例：She’s studying hard for fear that he should fall behind.
她努力学习，生怕跟不上。
四、虚拟语气用于让步状语从句中
在让步状语从句中，谓语动词多用动词原形来构成虚拟语气。
注：由even if 或even though引导的让步状语从句中，其从句的谓语动词形式与含有非真实条件从句的主从句中的谓语动词一样来构成虚拟语气。
经典练习：
1、Our idea is that the match____.
A)would put off
B)ought to put off
C)be put off
D)could put off
2、One of the requirements for a fire is that the material_____to its burning temperature.
A)is beated
B)will be heated
C)be heated
D)would be heated
3、That tree looked as if it _____for a long time.
A)hasn’t watered
B)didn’t water
C)hadn’t been watered
D)wasn’t watered
4、The business of each day, _____selling goods or shipping them, went quite smoothly.
A)it being
B)be it
C)was it
D)it was
参考答案:
1、答案选C)。根据虚拟语气的语法要求,that 从句中的动词用动词原形或“should+动词原形”的形式。所以C为正确选项。
2、答案选C)。requirement 后接一表语从句，从句的谓语用“should+动词原形”的形式来构成虚拟语气，四个选项中只有C符合。句意：产生火的必要条件之一是物质被加热到它的燃点。
3、答案选C)。as if引导一个表示与过去事实相反的虚拟语气的句子。主句的谓语动词是一般过去时，所以as if 后虚拟语气的谓语动词要用过去完成时，所以C是正确的。
4、答案选B)。be it selling goods or shipping them 是表示让步意义的虚拟倒装句，它是由whether it (might)be selling goods or shipping them这个句子省略whether后再将be 移至主语之前得来的。其它几项均不符合句子结构。句意：无论是售货还是运货，每天的业务都很不错
一、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。
二、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.
他要是准时到达就好了。
经典练习：
1、It’s already six o’clock now. Don’t you think it’s about time____?
A)we are going home
B)we go home
C)we went home
D)we can go home
2、If only the committee____the regulations and put them into effect as soon as possible.
A)approve
B)will approve
C)can approve
D)would approve
3、It’s necessary____the dictionary immediately.
A)that he will return
B)that he returned
C)that he return
D)that he has to return
4、She must have had an accident, or he____then.
A)would have been here
B)had to be here
C)should be here
D)would be here
5、I apologize if I ____you, but I assure you it was unintentional.
A)offended
B)had offended
C)should have offended
D)might have offended
解析：
1、答案选C)。在it’s about time that…..句型中，定语从句的谓语动词应用过去时来表示虚拟语气。所以C项是正确的。
2、答案选D)。if only表示一种愿望，谓语用“would+动词原形”表示对将来事实的愿望，所以D是正确的。
3、答案选C)。在由it is necessary 等引导的主语从句要使用虚拟语气，虚拟语气的谓语动词用“should+动词原形”或动词原形。
4、答案选A)。由or引出的是与事实相反的假设条件，因此空缺处应填入表示虚拟语气的谓语动词。前一个分句中表示的是过去的时间，所以后一分句要用would have done的形式。所以A是正确的。
5、答案选B)。本题中but分句中的it was 表明事情发生在过去，因此条件句应用过去完成时，表示与过去事实相反，所以B是正确的。
情态动词与动词的时态和语态
情态动词又称为情态助动词。英语中助动词主要有两类：一是基本助动词，如have, do, be等；二是情态助动词，如may, must, need等。情态动词与其他动词连用表示说话人的语气，可表达建议、要求、可能、意愿等。情态动词没有人称和数的变化。
一、情态动词+动词完成式
情态动词must, should, may(might), ought to, can(could), need, would等都可以与动词完成式连用作谓语，其模式为“modal verb+have+v-ed”。这类结构表示对过去所发生动作的推测或判断。但是，不同的情态动词所表示的意思又有所不同。
1、must+have+v-ed和can’t/couldn’t+have+v-ed
“must+have+v-ed”表示对过去事情较有把握的、肯定性的推测，常译为“一定”，“准是”，“肯定”。当must用于推测意义时，其否定形式通常不是must not, 而是can/could not.“can’t/couldn’t+have+v-ed”表示对过去事情的否定性推测，常译为“决不可能”，“不太可能”。
例：Since the ditch is full of water, it must have rained last night.
经典练习：
1、Mary’s score on the test is the highest in her class; she____have studied very hard.
A)may
B)should
C)must
D)ought to
2、You____her in her office last Friday; she’s been out of town for two weeks.
A)needn’t have seen
B)must have seen
C)might have seen
D)can’t have seen
3、Mary____my letter; otherwise she would have replied before now.
A)has received
B)ought to have received
C)couldn’t have received
D)shouldn’t have received
4、Dinosaurs are thought to____millions of years ago
A)die out
B)have died out
C)having died out
D)dying out
解析：
1、答案选C。must have+v-ed表示推测过去某事一定发生；may have+v-ed表示推测过去某事也许发生。Should/ought to have+v-ed表示“本应该…”根据句意，C为正确选项。
2、答案选D。can’t have+v-ed表示对过去发生事情的否定推测；needn’t+have+v-ed表示过去做了本不必做的事。根据句意D为正确选项。
3、答案选C。根据本句的后半句otherwise she would have replied before now可知，前半句是一个表示与后半句相应的虚拟过去情况的句子。Can’t/couldn’t
have v-ed表示过去不可能发生的事情。所以C为正确选项。
4、答案选B。像be believed/found/known/reported/said/supposed/thought后常跟不定式完成式，表达“据知，据报道”等意思，不定式的动作发生在被动结构(谓语动作)所表示的动作之前。根据语法要求B为正确选项。
一、should/ought to +have+v-ed和shouldn’t/ought not to+have+v-ed
“should/ought to+have+v-ed”表示过去应该做的事情却没有做，常含有后悔、责备、埋怨的口吻，常译作“本应当…..”，“应当….就好了”。“shouldn’t/ought not to+have+v-ed”表示过去不该做的事却做了，也常含有责备、不满的意思，常译为“本不应该….”。
例：With all the work finished, I should have gone to the party last night.
昨天晚上当所有的工作完成之后，我本来应该去参加聚会的。
例：You should not have gone back to work yesterday without the doctor’s permission.
你昨天没有得到医生的允许，不应该回去工作的。
二、may/might+have+v-ed
“may/might+have+v-ed”表示对过去事情的推测，但不十分肯定。Might比may语气缓和，口气更委婉；常译为“可能(或许)已经….”。
例：A traffic accident happened yesterday and a driver may have been hurt.
昨天发生了一场交通事故，可能有个司机受了伤。
三、could+have+v-ed
“could+have+v-ed”表示过去有可能或有能力做某事，而实际未做、未能实现的事；有时也表示轻度批评，可译为“本来可以”。
经典练习：
1、I didn’t send out my application form last week, but I _____.
A)had
B)would do
C)should have
D)might have to
2、With all his work on hand, he_____to the cinema last night.
A)mustn’t go
B)wouldn’t go
C)oughtn’t go
D)shouldn’t have gone
3、By next summer he_____at Harvard University for five years.
A)will have been studying
B)will study
C)have studied
D)will be studying
4、When Jim____his own house, he will install built-in stereo speakers in every room.
A)has
B)will have
C)had
D)had been
解析：
1、答案选C。本题第一句意义为：我上星期没有发出申请表。根据前后的逻辑意义，后一句应表示“我本应该发出”才是。C项省略了sent out,正合题意。
2、答案选D。shouldn’t have gone 表示“本来不该去的，但实际去了”的含义，符合语法规则，所以D为正确选项。
3、答案选A。“by(the end of )+将来时间”出现在句子中，句中谓语动词要用将来完成时或将来完成进行时来表达。所以A符合语法规则。
4、答案选A。当主句以将来时出现时，从句采用一般现在时来表示一般将来时，采用现在完成表示将来完成时。只有A符合语法规则。
一、needn’t+have+v-ed
“needn’t+have+v-ed”表示过去做了某事，但没有做的必要，即表达“本没必要….”之意。
例：You needn’t have done the washing up. I would have done it for you.
你本可不必洗那些餐具，我会替你洗的。
例：I needn’t have bought al that wine-only three people came.
其实我没有必要买这么多酒，因为只来了三个人。
二、情态动词+动词进行式
“情态动词+动词进行式”即“情态动词+be+v-ing”，表示推测或评论某动作是否正在进行。
例：He might still be playing basketball in the room.
他可能还在房子里打篮球。
三、情态动词+动词完成进行式
“情态动词+动词完成进行时”即“情态动词+have been+v-ing”，表示推测或评论过去某动作是否正在进行或一直在进行。
例：They may have been discussing the problem this morning.
今天上午他们可能一直在讨论这个问题。
经典练习：
1、I _____to him because he phoned me shortly afterwards.
A)ought to have written
B)must have written
C)couldn’t have written
D)needn’t have written
2、You_____all those calculations! We have a computer to do that sort of thing.
A)needn’t have done
B)must not have done
C)shouldn’t have done
D)can not have done
3、This is one of the rarest questions that_____at such a meeting.
A)has ever been raised
B)are raised
C)have ever been raised
D)is raised
4、I will overlook ____so rude to my sister this time.But don’t let if happen again.
A)you to be
B)you to have been
C)your being
D)your having been
解析：
1、答案选D。本题because从句表达的意思是：因为他之后不久给我打电话了。那么主句所表达的意思为：我本不必给他写信的。 D项意为“本不必给他写信”，其它三项均不符合题意。
2、答案选A。needn’t have done表示“本来不必要做，但实际上做了”的含义。符合题意。Must not 的意思是“不应、不可以”，后面一般不接完成式。其它几项也不符合题意。
3、答案选C。that引导的定语从句修饰questions,定语从句中的谓语动词需用复数；在结构“this(that/it )is +形容词最高级+名词+定语从句”中， 从句谓语通常用完成时态。所以C为正解选项。
4、答案选D。动词overlook在此意为“宽容”，要求以动名词做宾语，可首先排除A、B两项；时间状语this time 表示动名词动作已经发生，而且发生在谓语动作之前，所以须用动名词完成式，所以D项为正解选项。
题 目：虚拟语气中条件从句的几种特殊表达法
论文摘要：虚拟语气中条件从句的几种特殊表达法。混合虚拟条件句；省略if的倒装条件句；省略主句，只保留if(only)的条件句；含蓄虚拟条件句。
关 键 词：虚拟语气 条件从句 表达法
姓 名：海莎
单 位：北京大学附中河南分校
学 科：高中英语
联系电话：0371-62421417
虚拟语气中条件从句的几种特殊表达法
北京大学附中河南分校 海莎
虚拟语气是高中英语教学中的一个重点，又是一个难点。在虚拟语气的句子中，条件从句的表示方法较多 ，通常用if来引导，如If I were you, I would study much harder。在有些情况下，条件从句也可用其他方法来表示。下面谈几种虚拟语气中条件从句的特殊表达法。
一、混合虚拟条件句
如果条件从句的动作和主句的动作不是同时发生，主句和从句的谓语动词的形式应分别根据各自所表示的时间加以调整。这种句子叫做混合虚拟条件句。如：
If he had followed my advice, he would be quite all right now.（从句述说过去，主句述说现在）
If China had not been liberated, the working people would still be leading a miserable life.（ 从句表示与过去的事实相反，主句说明与现在的事实相反）
二、省略if的倒装条件句
如果条件从句的谓语动词包含有were或助动词、情态动词had, should, could，有时可将连词if省去，而将条件从句的主语置于were, had, should, could之后。这种用法主要用于书面语，如：
Were I (=If I were) in your place, I wouldn't give it up so early.
Had I (=if I had) known, I might have joined you in the discussion.
Should you (=If you should) be interested, I have a book on the subject you might like.
三、省略主句，只保留if(only)的条件句
虚拟条件句中的表示结果的主句有时形式上可以省略，但意义仍然存在。这种句子只保留一个if(only)条件从句，表达说话人的强烈愿望。如：
If(only)she were my sister！她是我的妹妹就好了！
四、含蓄虚拟条件句
有时虚拟条件句不用条件从句，而是通过上下文或用介词短语等表示出来。这种句子叫做含蓄虚拟条件句。下面列举几种。
1.在主语词组中表示含蓄条件
(1)主语是动词不定式短语，表示含蓄条件。
It would be good to leave the matter in his charge. 如果把这件事让他负责就好了。
该句可改写成：It would be good if we could leave the matter in his charge.
(2)主语是动名词短语表示含蓄条件。
Doing the work in that way would have cost much more time and money.
如果用那种方法做这项工作就会耗费更多的时间和金钱。
该句可改写为：If we had done the work in that way, it would have cost much more time and money .
(3)主语中带有定语从句表示含蓄条件。
A man who is always thinking of others would not have done such a thing.
如果一个人总为别人着想 ，他就不会做出这种事情来。
(4)主语中含有作定语的分词或形容词表示含蓄条件。
Anyone being his position would have made no reply.
任何人处在他那个位置，都不会回答的。
该句可改写为：If anyone had been in his position he would have made no reply.
A less complicated problem would have easily been solved.
如果问题不是很复杂的话，那么就很容易解决了。
该句可改写为：
If the problem had been less complicated, it would have easily been solved.
2.用介词短语表示含蓄条件
We could have done better under more favorable conditions.
如果在更好的条件下，我们会干得更好。
此句可改写为：If the conditions had been more favorable, we could have done better.
This change could not have taken place without a solid industrial foundation.
如果没有坚定的工业基础，发生这样的变化是不可能的。
此句可改写为：
If it had been without a solid industrial foundation, this change could not have taken place.
3.用but或but for引导含蓄条件句（but后跟从句，but for后跟短语）
But for your help, our experiment wouldn't have been so successful.
假如没有你们的帮助，我们的实验是不会如此成功的。
But for the storm, we should have arrived earlier.
要不是碰到暴雨我们会到得早一些。
We would have invited them to the dance, but they were too busy.
要不是他们太忙，我们会邀请他们来参加舞会的。
此句可改写为：If they had not been so busy, we would have invited them to the dance.
But that he is in hospital, He would go abroad for his summer vacation.
要不是生病住院，他就出国度暑假了。
该句可改写为：If he weren’t in hospital, he would go abroad for his summer vacation.
英语语法虚拟语气专项练习
一、单项选择:(共18小题,每题1分)
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.writen 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 ___ right away.
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 she 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.was
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 taken
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
二、用括号中所给动词的适当形式填空:(共10小题,每题2分)
1.If you ___ (arrive) ten minutes earlier, you could have seen them off.
2.It's time that we ___ (go) to the railway station.
3.If they___ (not help) us ,our experiment would have failed.
4.You're five minutes late.I suggested that you ___ (come )earlier tomorrow.
5.Mather often tells us that it is necessary that we ___ (drink) a glass of water after we get up.
6.She insisted that she___ (send) to work in the faraway small town.
7. ___ I not ___ (forget) his telephone number,I would have rung him.
8.He is busy now. If he ___ (be) free, he___ (go) with you.
9.The manager was in his office then. If he ___ (be) here, everything ___ (settle) in a minute.
10.Noisy as it was, he went on reading as if nothing ___ (happen).
三、完成句子(每空一词):(共10个空,每空2分)
1.真想不到我们俩会在这里见面.
It's strange that we___here.
2.如果没有参加玛丽的生日聚会的话,我们彼此就不会认识了.
If we hadn't taken part in Mary's birthday party, we___each other.
3.—这么近的路,我们应该步行到车站来.
—是啊,根本没必要乘出租车.
—We___ ___ ___to the station, it was so near.
—Yes. A taxi wasn't at all necessary.
4.万一明天下雨的话,我们将不得不推迟参观颐和园.
___ it rain tomorrow, we ___ ___to put off the visit to the Summer Palace.
四、句型转换:(共28个空,每空1.5分)
1.It is necessary for college students to master at least one foreign language.
It is necessary ___ college students ___ ___ at least one foreign language.
2.Without sunlight, there would be neither plants nor animals.
___ ___ ___ ___ sunlight, there would be neither plants nor animals.
3.She insisted on translating the sentence this way.
She insisted that the sentence ___ ___ ___ this way.
4.The students suggested going there on foot.
The students suggested ___ ___ there on foot.
5.She suggested that we should go to his help.
___ ___is that we ___ to his help.
6.Lucy didn't come to class today because she didn't feel well.
___ she ___ well, she ___ ___ ___ to class today.
7.I don't know French, so I can't talk to the French friends.
If I ___French, I could talk to the French friends.
8.He didn't take his parents' advice and he is not a college student now.
If he ___ ___ his parents' advice, he ___ ___ a college student now.
9.The professor helped me a lot and I finished the work.
I couldn't ___ ___ the work ___ the professor's help.
参考答案
一、1-5 CCADC 6-10 ABADA 11-15 BCDDB 16-18 DCC
二、1.had arrived 2.went (should go) 3.had not helped 4.(should) come
5.(should) drink 6.(should) be sent 7.Had; forgotten 8.were;would go
9.had been;would have been settled 10.were happening
三、1.meet 2.wouldn't have known 3.should have walked 4.Should; would have
四、 1.that; should master 2.If there were no 3.should be translated
4.they go 5.Her suggestion; go 6.Had; felt; would have come
7.knew 8.had taken; would be 9.have finished; without
