高中英语语法词法知识讲解—虚拟语气：.doc

高中英语语法词法知识详解虚拟语气一、动词的语气和种类: 语气(mood) 是一种动词的形式，用以表示讲话人对某一行为或事情的看法和态度。英语中的语气(mood)有三种，分别是陈述语气、祈使语气和虚拟语气。1.陈述语气(indicative mood): 陈述语气一般用来叙述事实或就事实提出询问，主要用于陈述句、疑问句和某些感叹句。eg. Where there is a will, theres a way. 有志者事竟成。 China lies in the east of Asia. Can you help me carry the box upstairs你能帮我把箱子搬到楼上吗？ How I missed the life in the countryside!我多么想念乡村的生活啊！2.祈使语气(imperative mood): 祈使语气表示说话人向对方提出请求或下达命令。eg. Come this way, please! 请这边走。 Dont make any noise, will you 别吵，行吗？ Do be careful when crossing the street.过马路时一定要小心。 Make yourself at home.3.虚拟语气(subjunctive mood): 虚拟语气(the subjunctive mood), 又称假设语气, 是谓语动词的一种形式, 表示说话人叙述的内容与事实相反, 在现实中并不存在, 或实现的可能性很小。虚拟语气是表示假设、愿望、建议、请求、命令、猜测、可能或主观打算等的一种语气,是每年高考必考的一个语法项目。eg. If I were a bird, I could fly in the air.如果我是一只小鸟，我就能在空中飞行。 I wish it were spring all the year round.但愿四季如春。 We only wish we could help. (表愿望) May good luck be yours! 祝你好运！ If there were no gravity, we should not be able to walk. (表假设) He suggested that we should all go to see the film.(表建议) 二、虚拟语气的形式:(1) 动词原形, 用于一切人称和数。eg. Long live the Communist Party of China! If that be so, we shall take action at once.(2) 动词的过去式, 用于一切人称和数, be的过去式用were。eg. If you loved me, you wouldnt say that. If I were you in your shoes, Id accept the terms.(3) had + 过去分词, 用于一切人称和数。eg. We would have called a cab, if Harold hadnt offered us a ride home. 假如哈罗德没有驾车送我们回家，我们就得叫出租汽车了。 If we had left earlier, we wouldnt have missed the train.(4)助动词(should) +动词原形, 用于一切人称和数。eg. They suggested that we (should) meet at the station. If you should see Celia, give her my best wishes.(5) 助动词(should) + have + 过去分词, 用于一切人称和数。eg. If the steamer (should) have left port at noon, it will be passing through the canal now. It is strange that she (should) have done it.(6) 助动词should(第一人称)和would(第二、三人称)+动词原形eg. If I were you, I should take his advice. He said he would go if I went.(7) 助动词should(第一人称)和would(第二、三人称) + have + 过去分词。(注意：美国英语常用would代替should)eg. If father hadnt sent me, I shouldnt have come. You wouldnt have seen her if it hadnt been for him.三、虚拟语气的具体用法:虚拟语气主要用于条件句即状语从句，还可用主语从句、宾语从句、表语从句、同位语从句和定语从句等。I.状语从句的虚拟语气： A. 条件句和结果主句的虚拟：(1). if条件句的虚拟条件句有真实条件句和非真实条件两种。真实条件句所表示的假设是可能发生或实现的,句中的条件与结果主句皆用陈述语气。 eg. If its fine tomorrow, well go outing. If I have enough money next year, I will go to Japan. If he doesnt come at 8, we wont wait for him. 如果他八点不来，我们就不等他了。 If a flood happened in the past, there was usually a great loss of life and property.过去发生洪水的话，常有很大的生命和财产损失。 We shall go there unless it rains tomorrow. 如果明天不下雨，我们将去那里。 Ill let you use my bike on condition that you keep it clean. 如果你能保持车子干净，我就让你用我的自行车。 非真实条件句所表示的假设则是不可能发生或实现的,句中的条件从句与结果主句皆须用虚拟语气。在含有虚拟条件句的复合句中，主从句的谓语都要用虚拟语气，现将其形式列表如下：动词形式 (时间)if条件从句结果主句与现在事实相反if + S. + 动词的过去式(be的过去式用were)I / We + should/might/could + 动词其他各人称+would/might/could 原形与过去事实相反if + S. + had + 过去分词I/we + should/might/could + have其他各人称+would/might/could + 过去分词与将来事实可能相反 if + S. + 动词的过去式( be的过去式用were) if + S. + were + to do sth. if + S. should + doI/we + should/might/could + 动词其他各人称+would/might/could 原形【注】条件从句用动词的过去式(be动词用were), 主句用should(第一人称)或would(全部人称)+动词原形。可用情态动词could, might代替should, would表示情态。. 表示与现在事实相反的假设和结果:eg. If I were you, I should( would , could, might) tell him the truth. 要是我是你，我就会告诉他真相了。(事实上我不是你) If she had time, she would( could, might) help me. 如果她有时间，她就会帮我了。(事实上她没有时间) If it were Sunday tomorrow, I would go and see my friends. 明天要是星期天的话，我就去看望我的朋友。 If I were you, I should go and try. 我要是你，我就去试试。 If wishes were horses, beggars might ride.如果幻想能成为马匹，叫花子都有了坐骑 I would go if they treated me like a slave. 要是他们把我当奴隶对待，我就走。. 表示与过去事实相反的假设和结果: eg. If I had known your telephone number yesterday, I should(would, could, might) have telephoned you.如果昨天我知道了你的电话号码，我就会给你打电话了。(事实上我昨天不知道你的电话号码。) If you had taken my advice, you wouldnt(couldnt) have failed in the exam.如果你听了我的建议，你就不会考试不及格。(事实上你根本没听我的。) If it had not rained this morning, I should have gone shopping. 今天早上要是没下雨, 我就去买东西了。 The flood might have caused great damages to the people if we had not built so many reservoirs. 倘若我们没有修建这么多的水库，洪水就会使人民遭受巨大的损失。. 表示与将来事实可能相反的假设和结果:表示在将来不太可能实现的条件从句有三种形式：(i) were / did:eg. If he were here tomorrow, I would speak to him. 明天如果他在这里的话，我就和他谈谈。 If you dropped the glass, it would break. 你要是把杯子掉下来，会打碎的。 If she had time, she could help me. 她要是有时间，就会帮我了。 -What would happen if I put the paper on the fire? -我若把只放在火上会怎么样? -It would burn. -纸会烧着。(ii) should do : 条件从句中不管什么人称都用should do，可表示有偶然实现的可能性。eg. If it should rain, the crops could be saved. 假如下雨, 庄稼可能就有救了。 We would trust him if he should be honest. 如果他真是诚实的, 那我们就相信他。(iii) were to do: 条件从句用were + to do。这种形式比较正式, 常出现在书面语中, 其假设成份很大, 实现的可能性很小。eg. If I were to do the work, I should do it in a different way. 要是我做这项工作, 我就会以不同的方式去做。 If the headmaster were to come, what would we say to him 假如校长来了, 我们对他说什么呢？对比：将来不太可能实现的三种非真实条件句中的虚拟语气对比eg. If it snowed tomorrow, I would stay at home. 如果明天下雪的话，我就留在家里。(常用形式) If it should snow tomorrow, I would stay at home. 如果明天下雪的话，我就留在家里。(可能性较小) If it were to snow tomorrow, I would stay at home. 如果明天要下雪的话，我就留在家里。(可能性最小)【注】: 在表示与将来事实可能相反的条件从句中, were to + 动词原形比较正式, 常用于书面语中。eg. If you were to go to Beijing, you would (could, might) have a chance to visit Tian An Men Square.(2)连词 if省略: 在书面语中，非真实条件句中有were, had, should时，可以省略if，而把were, had, should放在主语前，用倒装结构。eg. Were it necessary, I might go without delay. 如果需要的话，我可以立即去。(= If it were necessary.) Had you taken my advice, you wouldnt have failed in the exam.你要是听了我的建议, 就不会考试不及格了。(= If you had taken my advice.) Should I have time, I would call on her. 要是有时间, 我就去看她。(= If I should have time.)(3)省略if条件句:eg. You might stay here forever (if you wanted to.) We would have succeeded (if we had kept trying.) Your reputation would be ruined (if you should accept it.) I would appreciate a little of your time (if you were so kind as to give me a little of your time.) You could have done it yourself (if you had wanted to.) (You didnt do the work yourself because you didnt want to.) I wouldnt smoke (if I were you.) (You smoke often. I advise you not to smoke more.)(4)省略主句:非真实的条件句如省去结果主句,则表示一种不可能实现的愿望。这种条件句常用if only 来引导。If only.: If only位于句首引起的感叹句用虚拟语气，动词用一般过去时表示目前的愿望，用过去完成时表示过去的愿望，用would或could表示将来。eg. If only he knew the answer. 他要是知道答案就好了。(用过去时表示现在) If only I could speak several foreign languages！我要是能讲几种外语就好了！(用would / could表示将来) If only you had told me the truth before. 要是你以前告诉我真相就好了。(用过去完成时表示过去) If only you would listen to reason. If only he were here. / If I had never married. If my old friend were with me. If you had seen the wonderful film.注意：if only和wish的用法相同，表示的意愿也基本相同。eg. If only it would rain. 但愿天能下点儿雨！= How I wish it would rain. If only I had known her earlier! 要是我早点儿认识她就好了！= I wish I had known her earlier.(5)If it were not for(对现在的虚拟) 这是两个特殊的虚拟结构,表示一种特殊的情况改变了一切。 If it hadnt been for(对过去的虚拟) 常译成“要不是有了就”。eg. If it were not for the Party, we couldnt live such a happy life. If it hadnt been for the captain, they would have died. If it wasnt for me, youd have taken the wrong path a time ago. Were it not for the teacher, we couldnt learn so much knowledge. 【注意】(1) 在当代英语中,在很多情况下尤其在口语中,我们也可以用was来代替当主语是第一人称或第三人称单数时的虚拟式were。eg. If I were here tomorrow. 也可以说成：If he was here tomorrow. I wish I were a bird. 也可以说成：I wish I was a bird.(2) 但在正式文体中仍须用were,如须说: if I were in your position,又如as it were与were it not for you中的were亦不可代以was。(3) 倒装句型中的were不可被was来替换。eg. Were I in your position, I would not do it.如果我处在你的位置，我是不会干这件事的。(6)混合型虚拟语气: 虚拟条件句中的主句和从句涉及的动作发生的时间不一致, 这时主句和从句的谓语形式应按照各自动作发生的实际时间来表达。eg. If you hadnt watched TV yesterday, you wouldnt be so sleepy now. 如果你昨天不看电视，你现在也就不会这么困了。(从句yesterday说明过去，主句now说明现在) If they had left home early this morning, they would arrive in half an hour. 如果他们今天一早就离开家的话，再过半小时他们就该到了。(从句说明过去，主句说明将来。) If you hesitated this moment, you might suffer in the future. 如果你此刻犹豫不决，你将来会吃苦头的。(从句说明现在，主句说明将来) If you had studied hard last year, you would become a college student now. If she hadnt trained so hard, she wouldnt be able to run so fast. You would speak English well enough if you had practiced reading and speaking it every day. If I had spoken to him yesterday, I should know what to do now. You would be much better now if you had taken my advice. If father hadnt sent me, I should be here. If he knew this, it would have had to be by accident.【注意】: 如果条件从句用if I were,结果主句则可用表任何时间的虚拟形式。eg. If I were not busy, I would have come.(were表过去) If I were you, I would go. (were表现在)(7)含蓄型虚拟语气: 有时候，虚拟条件不是通过if引导的条件句来表示，而是暗含在上下文中(i) 用but for 、without(如果没有）等来代替条件从句；eg. Without electricity human life would be quite different. =If there were no electricity, human life would be quite different.(ii) 用otherwise、or(or else),even though等表示与上文的情况相反, 从而引出虚拟语气;eg. I lost your address. Otherwise, I would have visited you long before. =I lost your address. If I hadnt lost your address, I would have visited you long before.(iii) 虚拟条件通过but暗示出来; eg. He would have given you more help, but he was too busy. 他本来会给你更多的帮助, 但是他太忙了。(也就是说，如果那时他不忙，他可以给你更多的帮助。句中but he was too busy实际上暗示了一个虚拟条件如果那时他不忙) He would lose weight, but he eats too much 他本来可以减肥的，但是他吃的太多了。(也就是说，如果他吃得不多的话，他是可以减肥的。句中的but he eats too much实际上暗示了一个虚拟条件如果他吃得不多。)(8)unless条件句: eg. Unless I were well, I wouldnt be at school.(9)用suppose /supposing / providing等词表示if条件句的虚拟:eg. Suppose you were in my shoes, what would you do 假若你站在我的立场上，你会怎么办？ Suppose/Supposing it rains, what shall we do? Its a good idea, but suppose your mother were to find out? Suppose you were given a chance to study in America, would you accept?(10)用on condition that的条件句的虚拟： eg. He can use the bicycle on condition that he should return it tomorrow.(11). 条件可根据上下文推理出:：eg. It would do you no good. 这可能会对你没好处。(条件可能是if you should give up the job 如果你放弃这项工作的话) They could have won.他们本来是会赢的。(条件可能是if they had been patient 如果他们有耐心的话) Such mistakes could have been avoided. 这种错误完全能避免。(条件可能是if you had been more careful 如果你更加小心一点的话) Why didnt you tell me about it ? I should have helped you. 为什么你不告诉我？我会帮助你的。(条件可能是if you had told me about it 如果你当时告诉我的话)Did you go to see him yesterday?你昨天去看他了吗？I would have, but someone dropped over to my house for a visit. 原想去的，但有人到我家来玩了。 (条件是if no one had dropped over to my house for a visit 如果没人到我家来玩的话)(12).条件用其他形式来表示:eg. To talk with her, you would know she could not hear well. 如果你同她交谈，你就会知道她的听力不好。 (动词不定式带有假设的意思，相当于 If you should talk with her.) Left to himself, he could not have finished the work. 要是放任他的话，他是不可能完成工作的。 (动词的-ed形式表示条件 If he had been left to himself.)提示: 在很多情况下，虚拟式已变成习惯说法，很难找出其暗含的条件。eg. You wouldnt know.你不会知道。 I would like to go with you.我愿意和你一起去。【典题练习】1. If she had worked harder, she _.A. would succeedB. had succeedC. should succeedD. would have succeeded2. If my lawyer _here last night, he _me from going. A. had been, would have preventedB. had been; would prevent C. were; would preventD. were; would have prevented3. If he _, he _that food. Luckily he was sent to the hospital immediately. A. was warned; would not takeB. had been warned; wouldnt have taken C. would be warned; hadnt takenD. would have been warned; hadnt taken4. You didnt let me drive. If we _in turn, you _so tired. A. drove; didnt getB. drove; wouldnt getC. were driving; wouldnt getD. had driven; wouldnt have got5. If it _fine tomorrow, Ill go swimming.A. wereB. wasC. isD. will be6. If it _to snow tomorrow, they wouldnt go out.A. wasB. wereC. isD. would be7. You would have finished the work in time _. A. did you work harderB. have you worked harderC. had you worked harderD. do you work harder8. All the passengers would have died _for the captain. A. had it not beenB. were it notC. it hadnt beenD. it were not9. If you _the meeting yesterday, you _how to do the work now. A. came; will knowB. had come; would have knownC. should some; would knowD. had come; would know10. What would you have done if you _the first class.A. will miss B. would miss C. had missed D. missed11. If it _rain, we _get wet. A. is to; shouldB. were to; wouldC. were going to; wouldD. was going to; should12. If he _to the teacher attentively, he _the answer to the problem now.A. had listened; would have knownB. listened; would knowC. listened; would have knownD. had listened; would know13.I thought you would come back tomorrow. I would if I _to attend a meeting. A. dont haveB. didnt haveC. will not haveD. would not have14. “Did you catch the first bus this morning?” “No, I didnt.” “If you _earlier, you _the bus.” A. got up; would catchB. should get up; would catchC. had got up; would have caughtD. had got up; would catch15. Had I known her name, _. A. I will invite her to lunchB. she will come hereC. she would come hereD. I would have invited her to lunch16. If I _out of ink, I would have finished writing the paper. A. didnt runB. shouldnt runC. havent runD. hadnt run17. “Did you remind him of the meeting?” “No. If I _at home, I could have.”A. wasB. had beenC. wereD. should be18. If Henry had not pulled his cap low, he _by the police.A. might be recognizedB. might have been recognizedC. would have recognizedD. was to have been recognized19. If we had known that she had planned to arrive today, we _her at the bus station.A. may have metB. might metC. may metD. might have met20. _today, he would get there on Friday.A. Was he leavingB. If he leavesC. Were he to leaveD. If he is leaving21. Were it not for the debts, we _all right.A. would be B. would have been C. were D. are22. If he _tomorrow, I should give him the dictionary he needs. A. comes B. should comeC. would comeD. will come23. _, we should be glad.A. Were they to arrive tomorrowB. They were to arrive tomorrowC. They would arrive tomorrowD. They arrive tomorrow24. Had electronic computer not been invented, many problems of space flight _. A. could not have been savedB. could not be solvedC. can not be solvedD. could not have solved25. We _our lives had it not been for the policeman. A. would have lostB. should loseC. might loseD. could have lost26. I didnt see your sister at the meeting. If she _, she would have met my brother. A. has comeB. did comeC. cameD. had come27. Had you listened to the doctor, you _all right now. A. areB. wereC. would beD. would have been28. _I be free tomorrow, I could go with you. A. CouldB. ShouldC. MightD. Must29. _to do the work, I should do it some other way. A. If were I B. I were C. Were I D. Was I30. _your letter, I would have written back two days ago. A. If I receivedB. Should I receivedC. Had I receivedD. If I could have received31. _today, he would get there by Friday.A. Would he leaveB. Was he leavingC. Were he to leaveD. If he leave32. If it were not for the fact that you _ill, I would ask you to do this right now. A. wereB. had beenC. areD. be33. Should it rain, the crops _.A. would be savedB. would have been savedC. will be savedD. had been saved34. If I _you, I would try again.A. amB. wasC. wereD. be35. _, all the students would hear.A. If the teacher had spoken louderB. If the teacher will speak louderC. Had the teacher spoken louderD. If the teacher spoke louder36. What should we do if it _tomorrow?A. should snowB. would snowC. snowD. will snow37. If only I _my watch! A. hadnt lostB. havent lost C. didnt loseD. dont lose38. You _such a serious mistake if you followed his advice. A. may not makeB. might have not madeC. shouldnt have madeD. might not have made39. If only I _as young as you are!A. beingB. amC. beD. were40. If you _at school, you _a college student now. A. had studied hard; would have beenB. should have studied hard; should have been C. had studied hard; would beD. would study hard; must have beenB让步状语从句的虚拟: 让步状语从句指事实时，从句谓语动词用陈述语气。若从句内容表示现在和将来的假设情况，从句谓语动词用虚拟语气。(1) even if和even though意为 “即使”, 有假设之意主从谓语可用直接陈述语气也可用虚拟语气。用虚拟语气时，主从时态呼应与if条件句相同。eg. I wont lose heart even though Ive failed ten times. (直接陈述) Even if I had failed ten times, I wouldnt lose heart. (虚拟语气) The boy couldnt have been saved even if he had been tended without delay. 即使当时那个男孩得到及时照护,他的生命也未被挽救。 I wouldnt be angry with her even if I tried. 我即使想生她的气，也做不到。 I should say the same thing even if he were here. 即使他在这里，我还是要这么说。(2) though, whetheror, however, no matter等的让步状语从句eg. Though he (should) fail, there would still be hope. 即使他失败了，仍有一线希望。 Whether