虚拟语气一、虚拟语气的作用：1、表示与事实相反的或难以实现的情况2、表示主观愿望或某种强烈情感。
虚拟语气的用法：用在简单句、主语从句、宾语从句、表语从句、同位语从句和状语从句中。
二、虚拟语气用在简单句中,表示祝愿,命令.May you be happy. May you have a good time.May the friendship between us last long. Have a good journey!三、虚拟语气用在主语从句中的用法(1) 表情绪观点的形容词或名词也要用虚拟语气.necessary. important. impossible. natural. strange. surprising. funny. right. wrong. better. a pity等。
It is.....that 结构后的主语从句中的谓语动词都要用 should+原型或只用动词原型。
It's natural that he should feel hurt.(2) It is time (about time / high time) that... + (过去时或should + 动词原形)...。
It is high time I went home now. = It is high time I should go home.(3) It be + 过去分词＋that... (should)。
该结构中的过去分词是表示“建议、请求、命令”等词的过去分词：desired, suggested, advised, demanded, requested, ordered, proposed, insisted等。
与以上词语有关的主语从句、宾语从句、表语从句和同位语从句都需要用虚拟语气。
It is desired that the building of the house be completed next month.四、虚拟语气用在宾语从句中的用法1、在wish后的用法a、表示与现在事实相反的愿望，谓语动词用过去式 I wish I had your brains.我希望我有你那样的头脑。
b、表示与过去事实相反的愿望，谓语动词：had+done(动词过去分词） I wish I had known the truth of the matter.c、表示将来难以实现的愿望：谓语动词：should/would + 动词原形I wish I should have a chance again.2、虚拟语气用在希望、要求、建议和命令后的用法一想要(desire)二宁愿(prefer)三命令(order. command)四建议(advise. suggest. propose)五要求(demand. require. request. desire.insist)中，无论主句谓语动词为何种时态，从句的谓语动词都用：“should + 动词原形”或只用“动词原形”He suggested that we (should) take his advice. The police insisted that we (should) hand in the money. 注：（1）insist如果翻译成坚持某种动作才用虚拟语气，如果翻译成坚持某种观点就不用虚拟语气。
He insist he is a student. He insisted that he didn’t steal the knife.（2） suggest意为“建议”才用虚拟语气，意为“暗示、说明”则不用虚拟语气。
His face suggests that he is worried . What he said suggested that he was not the thief.五、虚拟语气在表语从句、同位语从句中的用法在suggestion, proposal, order, plan, idea, advice, decision等需要具体内容解释的名词后要使用虚拟语气，其谓语动词为：should + 动词原形，连接从句的that不能省略。
My suggestion is that we should go there at once. My suggestion that he should go there at once is reasonable. The order was that all the work be finished in two days. The order came that all the work be finished in two days.六、虚拟语气在条件状语从句中的用法1、表示与现在事实相反的情况： if+主语+did/be(were)+其他，主语+should/would/could/might+do+其他（1）If I were you, I would take an umbrella. （2）If I knew his telephone number, I would tell you. （3）If there were no air or water, there would be no living things on the earth.（4）If I had any money with me, I could lend you some. （5）If he studied harder, he might pass the exam.2、表示与过去事实相反的情况： if+主语+had done +其他，主语+should/would/could/might+have done+其他（1） If I had got there earlier, I should/could have met her.（2）If he had taken my advice, he would not have made such a mistake.3、表示对将来情况的主观推测 if+主语+did/should/were to do+其他，主语+should/would/could/might+do+其（1）If he should come here tomorrow, I should/would talk to him.(2) If there were a heavy snow next Sunday, we would not go skating.(3) If it ___ to snow next week, I would not go to visit that mountain village. A. is B. be C. were D. are(4) If my father ________ here the day after tomorrow, he ________ me at all.A. came, can’t see B comes, couldn’t see C. comes, couldn’t have seen D. came, couldn’t see七、需要注意的几个问题1、有时if引导的状语从句可以省略if,而把从句中的动词were,had 或should 移到主语前面.(1) Were she younger, she would do it . (2) Had he known her address, he would have gone to visit her.(3) Had she been here five minutes earlier, she would have seen her old friend.(4)What would have happened ,________ as far as the river bank?A. Bob had walkedB. if Bob should walkC. had Bob walkedD. if Bob walked2、虚拟语气表示该做（能做、需要做、可以做）而未做，或不该做（不能、不需要、不可以做）而做了。
(1) I could have helped you,but the car was too late. (2) She should have come to the party, but he .(3) He shouldn’t have told him the news.(4) He needn’t have finished the work yesterday, but he .(5) He ______ you more help, even though he was very busy.A. might have givenB. might giveC. should giveD. may give3、错综时间条件句：条件从句的动词动作可以和主句的动词动作时态不一致.If they had studied hard，they could do it easily now.If he had not taken my advice，he wouldn’t do it much better like this.Had I taken my umbrella with me when I came out this morning, I should not be wet now.4、含蓄虚拟条件句：1) 用with, without，but for等介词短语来替代条件从句, 它们都可以转换成由if引导的虚拟条件句。
We might have died without your help. =We might have died if you hadn’t helped us.Without the sun, nothing would grow. = If there was no the sun, nothing would grow.2) 用or, otherwise, but that, suppose/ supposing (that), provided / providing (that) 等引导的虚拟语气。
You didn’t come yesterday, or you would have seen him.I was very busy last week, otherwise I would have come to see you.Supposing I was still a little child, I would study hard from now on.3) 通过上下文来表示虚拟：这种情况下，需要加以分析。