第1个回答 2012-05-11
1.虚拟语气在条件句中的用法
(1)若表示与现在事实相反的假设,则条件从句中用过去式,主句中用过去将来式(would,should,could,might + 动词原形);若表示某事将来实现的可能性不大,则条件从句中用should + 动词原形也可用“were to+动词原形”或用过去式动词。如:
I would certainly go if I had time.(现在)
If it should rain,we wouldn”t go out.(将来)
If I knew German,I would read the paper to you.(现在)
If he were here,we could ask him.(现在)
(2)若表示与过去事实相反的假设,从句中用过去完成式,主句中用过去将来完成式(should,would,could,might + have + 过去分词)。如:
If I had set off a little earlier, I would have caught the train.
She would / might have come if she hadn”t been so busy.
If I hadn”t taken your advice,I would have made a bad mistake.
If only you hadn”t told him the news.
(3)含有虚拟语气的条件状语从句中,如有had,should,were 这三个词的话,在正式或书面语言中可将if省略,再将句子的主语和谓语动词实行全部倒装或部分倒装。如:
Had they time(=If they had time),they would certainly come and help us.
Should it be fine(=If it should be fine),we would go for an outing.
Were I go(=If I were you), I would go.
(4)若主句从句所指的时间不一致,即条件从句表示与过去事实相反,主句表示与现在事实相反;或者条件从句表示与现在事实相反,主句表真实情况,则从句中应采用与具体时间相对应的虚拟形式。如:
If it had rained last night(过去),It would be very cold today(现在).
If I had taken your advice(过去),I should have no trouble with the work now(现在).
2.虚拟语气在宾语从句中的用法
在动词suggest,order,demand,propose,request,command,insist等后的宾语从句中,用虚拟语气(即Should+动词原形或只用动词原形)来表示愿望、建议、命令、请求等。在动词wish /would rather后的宾语从句中,用过去式表示与现在事实不符,用过去完成式表示与过去事实不符。如:
I suggest that we(should)set off at once.
The doctor insisted that the patient (should)be X-rayed.
I wish I were as strong as you.
I would rather that you hadn”t told him.
3.虚拟语气在主语从句中的用法
在It is necessary/important/strange/natural;It is requested/suggested/desired/proposed;it is a pity等结构后的主语从句中要用虚拟语气,即Should+动词原形或只用动词原形。如:
It is necessary that he(should)be sent there at once.
It is requested that Professor Li(should)give us a speech.
It is desired that we(should)get everything ready by tonight.
4.虚拟语气在表语从句、同位语从句中的用法。
在 suggestion, proposal,idea,plan,order,advice等名词后的表语从句、同位语从句中要用虚拟语气,即should+动词原形或只用动词原形。如:
Our suggestion is that you( should)be the first to go.
My advice is that we(should)send for Doctor Li.
Do you know the order that you(should)keep watch?
5.虚拟语气在其他状语从句中的用法
在as if引导的状语从句中,用过去式表示与现在事实不符,用过去完成式表示与过去事实不符;在so that,in order that引导的状语从句中,常用should/would/could/might+动词原形来表示虚拟语气。如:
They talked as if they had been friends for years.
She stayed at home for a few days so that she could take care of her mother.
He took a taxi to the station so that she should not miss the train.
6.虚拟语气在定语从句中的用法:
在it is time后面的定语从句中常用过去式表示虚拟。