语法学习--虚拟语气(Unit7)

虚拟语气
语气，时态和语态都是动词的语法范畴。

语气分为三种：陈述语气，祈使语气和虚拟语气。

陈述语气用来陈述事实和对事实提出疑问。

祈使语气用来表示命令和请求。

虚拟语气用来表示说话人的一种主观愿望和假设的情况，而并非事实或难以成为事实，用于简单句，条件句以及其他的一些从句中。

Ⅰ. 虚拟语气在条件句中的运用
英语中的条件句一般有两种，真实条件句和非真实条件句。

虚拟语气用在非真实条件句。

非真实条件句包括虚拟条件句，推测条件句和错综时间条件句等。

1．虚拟条件句
虚拟条件句可以分为两类，一类是叙述与现实事实相反的情况，一类是叙述与过去事实相反的情况，其构成形式是：
条件从句结果主句
与现在事实相反If I(we, you, he, she,
it, they)+动词的过去
式（be动词的过去式
一律用were）
I(we, you, he, she, it,
they)+would+动词原
形
与过去事实相反 If I(we, you, he, she,
it, they) had+ 过去分
词
I(we, you, he, she, it,
they)+ would+
have+过去分词
注意；would 省略时也可以按句意换用should, could或might.
The flood might have caused great damages to the people if we hadn’t built so many reservoirs.
The conference wouldn’t have been so successful if we hadn’t made adequate preparations.
I am sorry I am very busy just now. If I had time, I would certainly go to the movies with you
2．推测条件句
对未来的事进行推测，在讲话人的心目中，虽然不认为推测条件的实现违背事实或绝对不可能，但却认为可能性极小。

这种怀疑和推测要用虚拟语气表示，其构成形式如下：
条件从句结果主句
If I(we, you, he, she, it, they)+动词过去式（be 动词的过去式一律用
were）
If I(we, you, he, she, it, they)+should+动词原形If I(we, you, he, she, it, they)+were to +动词原形I(we, you, he, she, it, they)+would+动词原形
If I were to see him, I would speak to him about it.
I would not believe it, unless I should see it
3．错综时间条件句
在错综时间条件句中，虚拟显见从句和主句的动作发生的时间不一致，因此，主句和从句的谓语动词要根据各自所指的不同时间选用适当的虚拟语气形式。

例如：
Had I taken my umbrella with me when I came out this morning, I should not be wet now.
如果我早上出门是带了伞，现在我就不会淋湿了
If you had spoken to him last time you saw him, you would know what to do now.
如果你赏赐看到他是跟他说一下，现在就知道该怎么做了。

4．虚拟条件句的简化
有些虚拟条件句可以不用从句表现出来，而是用介词，介词短语，动词不定式短语或利用上下文等形式表现出来，比如：with, without, but for , suppose, supposing, or, otherwise, but. Though, even, in the event that. 例如：
But for your help we couldn’t have succeeded.
要不是有你的帮助，我们是不会成功的。

They wouldn’t have reached the agreement so easily without that common ground.
没有共同的立场，他们是不会那么容易达成协议的。

She wasn’t feeling very well. Otherwise she wouldn’t have left the meeting so early.
她感到不舒服，不然她是不会那么早走的
Ⅱ。

虚拟语气在某些从句中的运用
1．动词wish后的宾语从句用虚拟语气
与现实事实相反，用were或动词的一般过去式，与过去事实相
反，用had+过去分词或would/could + have+过去分词；表示将来没有把握或不太可能的愿望，would/could(should, might)+动词原形。

例如：
I wish she were here.
I wish she would go with me tomorrow.
I wish she had taken my advice.
2．would rather(sooner), had rather, would as soon和just as soon后的句子用虚拟语气。

I’d rather you paid the money yourself.
I would sooner she painted the wall green next time.
3．if only后用虚拟语气。

If only she had known where to find you. 要是她知道去那里找你就好了。

If only I could speak several languages !我要是能将几门外语就好了。

4．虚拟语气用在suggest, order, demand, propose, command, request, desire, insist, require, decide, promise, arrange, ask, move, consent, determine, recommend, advise, intend, beg, resolve, argue等动词后的宾语从句中，这时，谓语动词要用动词原形或should+动词原形
She insisted that the seats (should)be booked in advance.
He advised that the doctor (should) be sent for.
5．虚拟语气用在advice, demand, order，decision, proposal, necessity, requirement, suggestion,等名词后的从句中, 这是谓语动词用原形或should+动词原形
The demand is that the job (should) be finished today.
6．形容词important, necessary, probable, possible, preferable. Advisable等，可以构成‘it is +形容词+that’, 其后的句子要用虚拟语气。

这时，谓语动词用原形或should+动词原形。

It is necessary that something (should) be done to deal with it.
7．It is (high, about) time……句型要求用虚拟语气, 这时，位于动词用过去式或should+动词原形（should不能省略）例如；It is high time that we were off.。