虚拟语气一、语气的定义和种类l、语气：语气是动词的一种形式，它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：(1)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：We are not ready. 我们没准备好What a fine day it is!多好的天气啊!(2)祈使语气: 表示说话人的建议、请求、邀请、命令等如: Open the door, please3)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: If I were you, I should study English. May you succeed! 二、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. (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:从 句主 句与现在事实相反动词的过去式（be的过去式一般用were）would/ should/ could/ might + 动词原形与过去事实相反had + 过去分词would/ should/ could/ might + have + 过去分词与将来事实相反动词过去式，should + 动词原形，were to + 动词原形would/ should/ could/ might + 动词原形注: 主句中的should只用于I、we，但在美国英语中，should常被would代替；从句中的should 可用于各种人称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. 他要是来了，让他给我打个Were I you (If I were you), I would not do it. 我要是你，就不做这事。
(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. 如果没有空气的话，就不会有生物了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 have finished the work.) 6、省去条件从句或主句：表示虚拟语气的主句或从句有时可以省略，但其含义仍可以推知。
1) 省去条件从句如: You could have washed your clothes yourself. 你本可以自已洗衣服的省去了"If you had wanted to")(2)省去主句(常用以表示愿望)如: If my grandmother were with me! If only she had not left!三、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that1)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)；2）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)；3)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. 即使生了病，他俩去办公室 (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. 他那样对待我，好像我是陌生人似的She talked about the film as if she had really seen it. 她谈论那部影片，就好像她确实看过一样注:如果表示的事情可能会发生，那么方式状语从句中的谓语动词可用陈述语气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. 格林先生说得很慢，好让学生听清楚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 our 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!May good luck be yours.3。