时间：2022-08-03 07:58:05
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，建议，推测，可能或纯粹的空想等。这种句子虽不像陈述句那么广泛，但也是英语语言运用中不可缺少的一部分，同时也是高考考查学生语言运用能力必考的语法项目。然而，学生在正确理解和熟练运用方面较有难度。本人根据自己的教学经验和体会，把虚拟语气的用法进行分门别类，帮助学生变苦学为乐学，巧妙掌握其用法，从而达到融会贯通的目的。虚拟语气的用法可以按照句型进行分类归纳记忆：‘
一．条件状语从句
如果条件状语从句中表示的条件根本不可能实现或实现的可能性很小，就需用虚拟语气。根据其表达的时间概念可分为与现在，过去和将来事实相反的假设。熟练掌握主句和从句的谓语表现形式是学好虚拟语气至关重要的一步。现归纳如下：
（一） 与现在事实相反
虚拟条件从句 主句
一般过去时（be动词一侓用were） would（should,could,might）+动词原形
e.g. They are not here now. If they were here now, we could ask them for help.
（二）与过去事实相反
虚拟条件从句 主句
had+过去分词 would（should,could,might）+have +过去分词
e.g If you had taken my advice ,you would have passed the driving test.
（三）与将来相反
虚拟条件从句 主句
一般过去时/should+动词原形/were to+动词原形 would（should,could,might）+动词原形
e.g She won’t come tomorrow. If she came ,I would show her my new computer.
特殊情况：
（一） 混合虚拟条件句
当虚拟条件从句中的动作和主句中的动作发生的时间不同时，从句和主句中的 谓语动词要根据各自具体时间来使用所需要的形式，这种句子叫做混合虚拟条件句。
e.g If you had not watched television so late last night, you would not be so sleepy now .（从句表过去，主句表现在）
（二） 含蓄虚拟条件句
有时假设的情况并不以if引导的条件从句的形式表示，而是通过一个介词短语或其它方式表示。常见的：without,but for,but that, otherwise ,or， but等等。如：
A but for/without/under/with等引导的介词短语（表条件）+主句
e.g But for your help , I should have drowned.
Without electricity, there would be no modern industry.
B otherwise/or/but等引导的虚拟语气句
（1） 真实情况（陈述句）+or/otherwise+虚拟语气句
e.g He was having a meeting,otherwise /or he would have come over to help us .
（2） 虚拟语气句+but+真实情况（陈述句）
e.g He could have done the work well, but he was so careless.
（三）省略和倒装
if引导的虚拟条件句的谓语动词中含有had ,were ,should时，可以将if省掉，再将这三个词置于句首构成倒装，句子句意不变。
e.g Should it happen（=If it should happen）,what would you do?
Were I you（If I were you ）,I would go.
Had he recognized me（If he had recognized me）,he would have come over.
二 。名词性从句
（一）用“should+动词原形”表虚拟，其中should可以省略
名词性从句如果是表示建议，命令和要求等含义或表示惊讶，喜悦，遗憾或惋惜等感彩，谓语一侓遵循此规则。为方便记忆，我们可以用一句话把这些动词的首字母串起来，即“I drop cars.”这些动词依次为insist, demand/desire, recommend, order, propose,command , advise/ask, request/require, suggest.
1．主语从句It is suggested/ordered/demanded…+that从句；It is +名词（a pity, a shame, a surprise, no wonder 等）；It is +形容词（necessary, important, strange, natural,vital等）。
e.g. It is no wonder that he (should)be sent to hospital at once.
It is natural that we should know it.
2. 宾语从句
e.g .She insisted that the seats (should )be booked in advance.
3.表语从句和同位语从句
以上动词对应的名词如：suggestion, requirement, desire, order ,advice, demand, proposal, recommendation等后面跟表语从句和同位语从句时，从句中也用（should）+动词原形。
e.g. The desire was that a treaty (should )be signed.
He issued the order that the troops (should) withdraw at once.
注意：
当suggest 表示“暗示，表明”；insist表示“认为，坚持说”时，其宾语从句中用陈述语气。
e.g. His expression suggests that he didn’t pass the exam.
She insisted that she was innocent.
(二) wish+宾语从句
从句虚拟类似if 引导的虚拟条件句的谓语表现形式。即:用一般过去时表示与现在事实相反，过去完成时表示与过去相反，could/would/might等+动词原形表示与将来相反。
e.g. I wish it were spring all the year around.
I wish we had finished it yesterday.
I wish I could fly to the moon some day.
(三) would rather+宾语从句 从句中用一般过去时表示与现在或将来事实相反，用过去完成时表示与过去事实相反。
e.g. I would rather you left for Beijing now/tomorrow.
I’d rather you had been here yesterday.
三．状语从句
（一）目的状语从句：连词in case ,lest ,for fear that 可用来引起虚拟语气，且常用should+动词原形表示虚拟。
e.g. We spoke in whispers for fear that we (/should/might )wake the baby.
Care must be taken in using this method lest overflow(should) occur.
He took his raincoat with him in case it should rain。（虚拟语气，should 常不省略）
OR: He took his raincoat with him in case it rained.（陈述语气）
（二）方式状语从句：连词as if/as though 引导的方式状语从句也用虚拟语气，情况类似if引导的虚拟条件句。
e.g. She talks as if she knew all about it..（与现在事实相反）
Father behaved as if nothing had happened.(与过去事实相反)
The old man talks about it again and again as though he would never end.(与将来相反)
注意：as if /as though放在系动词（appear, seem ,look, smell, taste等）之后引导表语从句时，有时也用虚拟语气,表示与事实相反。
e.g. When a pencil is partly placed into a glass of water ,it looks as if it were broken.
（三）让步状语从句：连词even if /even though/though/however等引起的虚拟语气，表示与现在事实相反，从句用may/might +动词原形（有时may/might可以省略）；表示与过去事实相反，从句用过去完成时。主句谓语变化类似虚拟条件句的主句变化情况。
e.g. However dangerous it might be, he would have a try.
Even though I had been very busy then ,I would have helped you.
四 特殊句式
1.It is (about /high) time +that从句
从句中用一般过去时或should+动词原形表示虚拟语气，但should不可以省略。
e.g. It’s time that you had /should have a rest.
2. if only 引导的感叹句
用一般过去时或would /could+动词原形表示与现在或将来事实相反的愿望；用过去完成时表示与过去事实相反的愿望。
e.g. If only you would listen to our advice!
If only he were at home now!
If only I had not been busy last week!
3.had hoped/meant/wanted/expected/planned…+to do 或hoped/meant/wanted/ expected/planned…+to have done 表示未曽实现的希望，打算，意图，诺言等
e.g.I hoped to have seen /had hoped to see you yesterday, but I didn’t have any time.
4. was/were to have done 本打算做却没做
e.g. I was to have finished the work yesterday, but I didn’t.
5.was coming/going/ planning/expecting/looking forward to…等有时也用来表示本打算做而实际没做的事。
e.g. He was coming to see me ,but unfortunately he was ill.
I was going to playing tennis with you tomorrow.
6.was/were supposed to have done 理应做而没做
e.g. Mr. Wang was supposed to have arrived by 8 o’clock,but he hasn’t turned up so far..
7情态动词+have done 也可以用来表示与过去相反的虚拟。
might have done 本来可以
could have done本来能够
needn’t have done 本来没有必要做却做了 should(ought to) have done本该做而没做
shouldn’t(oughtn’t to) have done 本不该做而做了
e.g. You might/could have passed the exam, but you were too careless.
We should have told him this earlier.
You needn,t have watered the flowers ,for it is going to rain.
Since my car is not in use today,she shouldn’t/oughtn’t to have rented the car.
收稿日期：2012-04-10