第七讲 虚拟语气

虚拟语气
一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，就是真实条件何。

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:
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.
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.
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.
If it were to snow this evening, they would not go out.
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.
Were I you (If I were you), I would not do it.
(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.
But for your help (If it hadn’t been for your help) I couldn’t have done it.
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.)；
I would have finished the work, but I have been ill. (If I hadn’t been ill, I would hav e finished the work.)
二、虚拟语气的其他用法
l、虚拟语气在主语从句中的用法：在"It is important (strange，natural，necessary)that…"这类句型里，that所引导的主语从句中的谓语动词常用“should十动词原形”结构，表示某事是"重要"、"奇怪"、"自然"、"必要"等意义。

如: It is important that every member (should) inform himself of these rules. 重要的是每个成员知道这些规则。

2、虚拟语气在宾语从句中用法：
(1)在动词wish后的宾语从句中，表示与现在或过去的事实相反，或对将来的主观愿望，从句通常省略连词that。

a.表示对现在情况的虚拟:从句动词用过去式或过去进行式(be动词一般用were)。

如: I wish I knew the answer to the question. 我希望知道这个问题的答案。

(可惜不知道)；
b.表示对过去情况的虚拟:从句动词常用"had十过去分词"。

如: I wish (wished) I hadn’t spent so much money. 我后悔不该花那么多钱。

(实际上已经花掉)；
c.表示对将来的主观愿望:谓语动词形式为"would十动词原形"。

此时要注意，主句的主语与从句的主语不能相同，因为主句的主语所期望的从句动作能否实现，取决于从句主语的态度或意愿(非动物名词除外)。

如: I wish it would stop raining. 但愿雨能停止；I wish you would come soon. 但愿你立刻来。

(2)在suggest，demand，order，propose，insist，command，request，desire等动词后的宾语从句中，谓语动词用“should + 动词原形”，表示建议、要求、命令等。

如: I demand that he (should)
answer me immediately. 我要求他立刻答复我。

3、虚拟语气在状语从句中的用法
(1)在带有even if/ even though引导的让步状语从句的主从复合句中，主句和从句都用虚拟语气，动词形式与含有非真实条件句的虚拟语气相同。

如: Even if he had been ill, he would have gone t his office.
(2)由as if或as though引导的状语从句表示比较或方式时。

从句谓语形式为动词的过去式(be用were)或“had十过去分词”。

如: He treated me as if I were a stranger.
She talked about the film as if she had really seen it.
(3)在in order that或so that引导的目的状语从句中，谓语动词多用“could或might（有时也用should）+ 动词原形”。

如: Mr green spoke slowly so that his students could (might) hear clearly.
4、虚拟语气在定语从句中的用法：在"It is time (that) …"句型中，定语从句的谓语动词常用虚拟语气表示将来，动词形式一般用过去式，意思是"该干某事的时候了"。

如: It’s (high) time we did o ur homework.
5、虚拟语气在简单句中的用法
(1)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，常见于日常会话中。

如: It would be better for you not to stay up too late.
(2)在一些习惯表达中。

如: I would rather not tell you.
(3)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）。

如：May you be happy!祝你快乐！
May good luck be yours.祝你顺利。