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专题09 情态动词和虚拟语气易错点1 情态动词的误用 1. Some people who dont like to talk much are not necessarily shy; they _ just be quiet people. A. must B. may C. should D. would【错因分析】考生容易误选C项，认为是一定是，实际上这里表示可能性。【参考答案】Bmay/might接动词原形时表示对现在情况的推测，意思是可能。She thought it might be wise to try her luck here. 她认为在这儿碰碰运气也许不错。2. What does the sign over there read? No person _ smoke or carry a lighted cigarette, cigar or pipe in this area. A. will B. may C. shall D. must【错因分析】考生容易误选A项，认为这里要用will表示将来或意愿。shall在本句中用于第三人称，表示警告和禁止；will表示现在的意志、愿望等，意为要，希望；may表示许可，或用于请求许可，意为可，可以；must意为必须，要，应当。【试题解析】句意：那边的那个标志说的什么？任何人都不准在这个区域吸烟、或携带点着的香烟、雪茄或烟斗。根据语境可知这里表示警告和禁止，因此要用should。【参考答案】Cshall用作情态动词主要有以下两个用法：（1）用于第一、三人称的疑问句，表示征求对方意见。Shall I help you? 要不要我帮你？Shall I open the window? 要我把窗子打开吗？Shall she go to the concert with us this evening? 她要和我们一起去音乐会吗？（2）用于陈述句中表示允诺、告诫、警告、威胁、命令、规定、必然性等（可用于各类人称）。You shall suffer for this. 你会为此事吃苦头的。（表威胁）Each petitor shall wear a number. 每个参赛者要戴一个号码。（表规定）You shall hear everything as soon as you e. 你一来就可以听到所有的情况。（表允诺）You shall go to the front at once. 你马上到前线去。（表命令）Dont worry. You shall get the answer this very afternoon. 不要着急，你今天下午晚些时候可以得到答案。（表允诺）He shall be sorry one day. I tell you. 我告诉你，他早晚会后悔的。（表警告）Nothing shall stop us from fighting against pollution. 什么也阻止不了我们与污染作斗争。（表决心）1.【2018北京卷单项填空】In todays information age, the loss of data _ cause serious problems for a pany.A. need B. should C. can D. must【答案】C2. I think the work _ be pleted ahead of time. 【解析】句意：我认为这项工作可以提前完成。由句意可知这里表示说话人的一种看法，故填can。【答案】can【名师点睛】此题有些考生可能会认为这里是要求工作必须提前完成而误填must，因此在做此类题时，一定要结合语境，仔细推敲语境暗含的意思，从而提高做题的正确率。3. Its the office! So you _ know eating is not allowed here. Oh, sorry. A. must B. will C. may D. need【答案】A【名师点睛】must常用来表示禁止、命令，这时主要用于否定句中。You must not speak ill of others. 你一定不要说别人的坏话。You must not go there. 你不准去那儿。情态动词的基本用法（一）情态动词的特点情态动词，在英文中主要用来表示说话人的看法、态度等。它很接近中文里的能愿动词。从用法上来说，它有这样几个特点：1. 各个情态动词自身都有一定的词义。2. 情态动词不能在句中独立担当谓语。3. 情态动词在句中不受任何人称、性、数变化的影响。4. 情态动词后接的不定式（除ought外）都不带to，即接动词原形。（二）常用情态动词的基本用法英文中的情态动词主要有：can, could; may, might; must; ought; need; dare, dared，另外，shall, will, should, would在一定的场合也可用作情态动词。He can speak five languages. 他会说五种语言。She must have arrived home by now. 现在她准到家了。We should study hard for our motherland. 我们应该为祖国而努力学习。They neednt be in such a hurry for there is enough time for them. 他们还有足够的时间，用不着这么慌张。1. can, could 能，会could可以看作是can的过去式，这两个词除了时态不相同外，在表达意思的许多方面是相同的。当然could也有自己独特的用法。（1）表示脑力或体力上的能力Nobody can stop the development of science. 谁也无法阻止科学的发展。She can sing that song in English.她能用英文唱那歌。He can submerge to a depth of about twenty meters. 他能潜入约二十米深的水中。He could hardly support his family before he found the new job.他在找到那份新工作前几乎无法养家。I could not understand the lecture on the puter given by Mr. Smith.我听不懂史密斯先生作的那个关于计算机的讲座。（2）表示客观上的可能性You can borrow this useful book from the library.你可以从图书馆借到这种有用的书。A more suitable person than him for the job cannot be found. 不可能找到比他更适合这份工作的人了。Now people can skate on the lake. 现在人们可以在湖上滑冰了。When the storm stopped, the plane could take off. 当风暴停下来时，飞机可以起飞了。（3）表示主观上的允许Can I ask you some questions about it? 我可以问你有关这件事的几个问题吗？You cannot leave here till I e back. 直到我回来你才能离开。Such kind of thing cant happen anymore later. 这类事以后不准再发生了。Can you tell me how to get to the airport? 你能告诉我怎么去机场吗？Could you tell me how to get to the airport? 您能告诉我怎么去机场吗？Could I be forgiven my negligence? 请原谅我的疏忽，行吗？（4）表示猜测、怀疑或惊诧（用于否定句、疑问句或感叹句中）How can / could you be here? 你怎么会在这儿？She couldnt / cant be so stupid to do that. 她不可能蠢得去做那种事吧。He couldnt / cant be over seventy. 他不可能有七十多岁了。Where could / can the boy be now? 那孩子现在能在哪儿呢？另外，could还常用于表示较客气委婉的看法、提问及用于虚拟语气的结构中。这时候，could就不可以看作是can的过去式了。而是could自己独特的用法。Could you speak a little slowly? 您能稍微说慢一点儿吗？I could e earlier if asked. 如果要让我早一点来，我可以来早一点。Im afraid that we couldnt give you any definite answer at this moment.恐怕我们这时候还无法给予你任何确切的答复。We would appreciate it if you could offer us any help.如果您能为我们提供帮助的话，我们将不甚感激。You could have done better if you had worked harder at it.如果你再加把劲，你本来可以做得更好一些的。2. may, might 或许，可能，可以might可以看作是may的过去式，这两个词除了时态不相同外，在表达意思的许多方面是相近的。当然may 和might又都有一些各自不同的独特用法。（1）可能性I may be busy from tomorrow on. 从明天起我可能会忙起来。I wondered if they might agree with the idea. 我想知道他们是否会同意这种想法。She thought it might be wise to try her luck here. 她认为在这儿碰碰运气也不错。You may catch sight of the sunrise from here when you get up before 5 in the morning.你在早晨五点钟以前起来，或许能从这儿看到日出。（2）表示允许May I e in? 我可以进来吗？Id like to have a smoke here if I may. 如果可以的话我想在这儿抽一支烟。The librarian told her that she might return the book to the library in three days.图书馆理员告诉她说，她可以在三天后还那本书。At the press conference, a news reporter asked the chairman if she might trouble him with a question about Taiwan issue. 在记者招待会上，一位新闻记者问大会主席她是否能提一个有关台湾问题方面的问题。（3）may可以用来表示祝愿，也常用于表示目的或让步的状语从句中：May that day e soon. 但愿那天早日到来。May you succeed in winning the first prize in the game. 祝愿你比赛夺冠成功。May you continue in your efforts and achieve greater successes. 祝愿你继续努力并取得更大的成功。（4）might也常用于表示目的等状语从句中，或用于虚拟语气的结构中：I could not convince him, try as I might. 我无论用什么样的办法也不能说服他。He died so that the others might live. 为了其他的人能活下去，他自己牺牲了。One error in calculation might ruin the whole project. 计算中出一点错就可能毁掉整个工程。They left off earlier on that day so that they might catch the first train.那天，他们为了赶上头班车动身早一些。If you had made better use of your time, you might have learned more.假若你将自己的时间利用得更好一些，你本可以学到更多东西的。 注意：在回答以may引导的问句时，一般说来避免使用may，以免显得太严厉、或不太客气，而改用其他方式。May I e in? 我可以进来吗？Yes, please. / Sure. / Certainly. 请进。Please dont. 请不要进来。No , you mustnt. 不行。3. must 应该，必须，一定（1）表示出于职责、义务该做某事We must protect peoples rights. 我们应该保护人民的利益。Everyone must be loyal to his motherland. 每个人都应该忠于自己的祖国。You must serve the people when you grow up. 你们长大成人后应该服务于人民。Students must work hard at their study. 学生应该努力学习。（2）表示出于主观意识而必须要做某事We must speed up the pace of our economic reform. 我们必须加速经济改革的步伐。We must keep steps to the scientific development. 我们一定要与科学的发展保持步调一致。You must hurry up or youll be late. 你必须得快点儿，不然会迟到的。 注意：在这种用法中must表示出于主观意识而必须要做某事；have to却表示由于某种客观原因而不得不做某事。除此以外，have to自身有时态的变化形式。I have to go now for Ive got a meeting 15 minutes later.我现在必须要走了，因为我15分钟后有个会要开。He has to be back home by five to fetch his son from kindergarten.他必须在五点钟前回家去幼儿园接他的儿子。Jenny had to tidy up the room before her mother came back.珍尼不得不在她妈妈回家以前将房间整理好。 注意：在这种用法中，回答以must引导的问句时，若是否定答复，不可以用mustnt 而需要用neednt 或是dont have to，因为mustnt意思是绝不能、一定不要，而没有不必的意思。Must we hand in our exercises today? 我们今天必须交作业吗？Yes, you must. 是的，必须交。No, you neednt（or, you dont have to ）. 不，不必今天交。（3）表示禁止（用于否定句）You must not speak ill of others. 你一定不要说别人的坏话。Cars must not park here. 这里禁止停车。Smoking must not allow in the office. 严禁在办公室吸烟。You mustnt talk to girls like that. 你绝不能那样对女孩子说话。（4）表示猜测、推测，must常用于肯定句中表示猜测。对现在或未来的事进行猜测时，后接动词原形；对已经发生的事进行猜测时，后接have + 过去分词。You must be tired after working so long. 你工作这么长时间，肯定累了吧。It must be that naughty boy crying outside. 肯定是那个调皮的孩子在外面大叫。It must have rained last night for it is so wet outside. 外面这么湿，昨晚肯定下雨了。The idea must be accepted by the society sooner or later.这种想法肯定迟早会被社会所接受的。I didnt see you in class yesterday. You must have been absent.我昨天上课没见着你，你肯定没有来。4. ought 应该（后接带to的不定式构成谓语动词）（1）表示出于职责、义务该做某事You ought not to be so careless in your work. 你不应该在工作上如此粗心大意。We ought to study hard for the sake of our motherland. 我们应该为了我们的祖国而努力学习。His doctor said to him that he oughtnt to smoke so much. 他的医生说他不应该抽这么多烟。Oughtnt you to give us a chance to try? 你难道不应该给我们一个尝试的机会吗？（2）表示极有可能发生某事As an auto repairman, Dick ought to know what is wrong with the car.作为一个汽车修理工，狄克应该知道这部车的毛病所在。If we set off right now, we ought to be able to get there in time.如果我们马上出发，我们应当能够按时到达那里。Tomorrow ought to be a nice day for we have such a fine sunset today.今天有这么好的晚霞，明天准是个晴天。5. need需要（用于否定句和疑问句）There are still one and a half hours to go, we neednt be in such a hurry.还有一个半小时，我们无需如此慌张。I hardly need say how much we missed you. 不用说我们是多么地想念你。Need you go so soon? 你需要这么早就去吗？You need have no anxiety on my account. 你不必为我而着急。6. dare, dared敢（用于否定句、疑问句和疑问句）Dare you stay here alone in the night? 你敢在夜里待在这儿吗？Nobody dared mention that matter. 没有人敢提那件事。How dared you say that to her? 你怎么敢对她说那件事？Even if you dare do it, I wont allow you to because its too dangerous.即使你敢做，我也会让你做那件事，因为太危险了 7. shall用作情态动词时，适用于第二人称和第三人称。主要表示下面几层意思：（1）许诺You shall hear everything directly you e. 你一来就可以听到一切了。Whatever you want you shall have, said the Fairy. 仙女说：你想得到什么，你就可以有什么。I dont want to be hard on your daughter; she shant be pressed.我不想对你女儿太严厉，她不会受压制。I promise that you shall see her again before long.我保证你不久就能再见到她。（2）命令You shall e to my office immediately. 你必须马上来我的办公室。She shall not stay in my garden. 她不可以待在我的花园里。He shall not e into my study. 不许他进我的书房。You shall do as you are told. 按告诉你的那么做。（3）决心（表示某事一定会发生）That day shall e. 那一天一定会到来。It has been decided that he shall be given the job. 已经决定让他做那份工作了。This law shall e into effect on January 1st 2001. 这个法律于2001年1月1日生效。（4）规定Each petitor shall wear a number. 每个参赛者要佩戴一个数字标。The renter shall keep the house in a neat and orderly state. 租赁者要保持房屋整洁有序。The supplier shall make shipment before October and the purchaser shall make payment within 15 days afterreceipt of the goods. 卖方十月以前装运，买方在收到货物后十五天内付款。8. should用作情态动词时，有时表示具体的意思，有时没有意义。主要用于下面几个方面：（1）表示出于职责、义务该做某事You shouldnt e to such a decision hastily. 你不应该匆忙做出这么一个决定。You should write to your parents at least once a month. 你应该至少每月给你父母亲写一封信。We should read English aloud every morning. 我们应该每天早晨朗读英文。They should do it for their own good. 为了他们自己利益他们应该做这件事。（2）表示对某种情况的估计She shouldnt be out in such an early morning. 她不会这么一大早就出去了吧。This book should be published in two months at most. 这本书最多两个月后就会出版的。The effect of the tax should be felt in higher prices.人们可能会从各种上涨的物价中感觉到这种税的影响的。The event should lead them to a even worse economic crisis.这次事件可能会将他们引向更严重的经济危机。（3）表示惊讶、失望等情绪I think it is dreadful that anyone should be so miserable. 我认为，竟然每个人都如此伤心就太糟糕了。Why should I pay him for nothing? 我干吗要白白付给他钱？It seems so unfair that this should happen to me. 这件事竟然发生在我身上，似乎太不公平了。Its strange that it should be so cold today. 奇怪，今天怎么会这么冷。（4）用于某些从句中表示虚拟语气The doctor insisted that the girl should be hospitalized. 大夫坚持认为那个女孩要住院治疗。She stood away so that he should enter the room first. 她让到一边，好让他第一个进入房间。Ill write it down lest I should forget it. 我将它记下以免遗忘。Take an umbrella with you in case it should rain. 带上雨伞，以防下雨。9. will, wouldwould可以看作是will的过去式，这两个词除了时态不相同外，在表达意思的许多方面是相近的。当然will 和would又都有一些各自不同的独特用法。（1）用于第二人称疑问句，表示请求（在这种用法中would使语气更为客气、委婉）Will you tell her that Ill be back in twenty minutes? 请告诉她我二十分钟后回来，好吗？If you want help, just let me know, will you? 你需要帮助就告诉我，好吗？Would you tell me how to get to the shopping center? 您能告诉我怎么去购物中心吗？Wont you e in and have a little whisky?你要不要进来喝一点儿威士忌？（或是：你进来喝一点儿威士忌，好吗？）（2）用于表示愿望Go where you will. 去你想去的地方吧。I will pay you at the rate you ask. 我会按你要的利率付给你钱的。He wouldnt let the doctor take his blood pressure. 他不愿意让大夫给他量血压。They had to obey whether they would or not. 不管他们愿意与否，他们必须要遵从。（3）表示习惯、倾向（可译成总是会、老是，等 ）Sometimes the cat will lie there all afternoon. 有时侯，那只猫会整个下午都躺在那儿。Oil and water will not mix. 油和水不能混合。He would sit there for hours, doing nothing at all. 他总是在那儿一坐就是几个小时，什么都不干。（4）表示猜测（可译成一定是、想必，等 ）This will be the house youre looking for. 这想必就是你要找的房子吧。He will have gone back to New Zealand. 他一定是回新西兰去了。That would be in 1999, I think. 那大概是在1999年吧。（5）will用于表示决心（可译成一定要，决心等 ）We will never talk about that subject again. 我们决不会再谈论这个话题了。I will make this puter work even if I have to stay up all night.我即使整晚不睡觉也一定要让这台计算机工作起来。（6）would常用于虚拟条件句，表示与事实相反或不太可能实现的情况But for your help we would have been late. 要不是你帮忙我们就迟到了。Well, I wouldnt worry about it. It wont do me any good.好了，我不会担心那件事的，因为它不会给我带来什么好处。易错点2 混淆情态动词+have done各种句式的不同含义1. Where is my dictionary? I remember I put it here yesterday. You _ it in the wrong place. A.must put B.should have put C.might put D.might have put【错因分析】考生容易误选A项，原因是受汉语表达习惯的影响，认为你一定是把它放错地方了。根据前面的语境可判断出，本题考查情态动词表推测的用法。所以要用might have done。should have done表示(过去)本来应该做某事。must意为一定，是肯定的推测，与所提供的情景矛盾。might put表示现在发生的事。【参考答案】D情态动词have done用法must have done一定做过某事，其否定形式为cant/couldnt have donecan/could have done本来能够做某事但却未做可能做过某事cant/couldnt have done不可能做过某事may/might have done或许/可能做过某事should/ought to have done本该做但却未做，其否定形式表示本不该做但却做了neednt have done做了本没有必要做的事情1.【2018天津卷单项填空】 I cant find my purse. I_ it in the supermarket yesterday, but Im not sure.A. should leave B. must have leftC. might leave D. could have left【答案】D2.That car nearly hit me; I _. A. might be killed C. may be killed B. might have been killed D. may been killed【解析】句意：那辆小轿车差点撞到了我，我差点被撞死。被撞死是过去可能发生而实际并没有发生的事情，因此要用might have been killed。【答案】B【名师点睛】may/might have + 过去分词表示对过去已经发生的事进行推测判断，一般只用于肯定句或否定句中（疑问句中用can或could），may/might的意思是可能，也许，may/might的意思是可能不（没有）。Nobody stopped him; he might have been a passengers child. 没人制止他，他或许是一个旅客的孩子。Its no use going to his house. He may not have gone home; he may have gone somewhere else. 去他家没有用，他可能没有回家，可能去别的地方了。注意：might have + 过去分词可用来表示过去可能发生而没有发生的事情。You were so careless that day. You might have made a bad mistake. 那天你太粗心了，你有可能犯错误的。（事实上并没有犯错）1.must have done表示对过去事情的肯定推测，译成一定做过某事，该结构只用于肯定句。 It must have rained last night, for the ground is wet. 昨晚一定下雨了，因为地面还是湿的。You must have been mad to speak to the servant. 你和仆人说话，一定是发疯了。2.cant have done表示对过去事情的否定推测，译成不可能做过某事。Mr Smith cant have gone to Beijing, for I saw him in the library just now. 史密斯先生不可能去北京了，我刚才还在图书馆见过他。Mary cant have stolen your money. She has gone home. 玛丽不可能偷你的钱，她回家去了。3.can have done表示对过去行为的怀疑，用于疑问句，译成可能做过吗？。There is no light in the room. Can they have gone out? 屋里没有灯，他们可能出去了吗？There is nowhere to find them. Where can they have gone? 到处找不到他们，他们可能到什么地方去呢？4.could have done是虚拟语气，表示对过去事情的假设，意思是本来能够做某事而没有做。He could have passed the exam, but he was too careless. 本来他能够通过考试，但是他太粗心。5.may have done表示对发生过的事情的推测，意思是可能已经或也许已经，用于肯定句中。 What has happened to George? 乔治发生了什么事？I dont know. He may have got lost. 我不知道，他可能迷路了。6.might have done表示对过去事情的推测，might与may意思相同，但可能性更小。多用于虚拟语气结构中。 She might have achieved greater progress, if you had given her more chances. 如果你多给她点机会，她可能已经取得了更大的成绩。7.would have done虚拟语气，表示对过去事情的假设，意思是本来会。I would have told you all about the boys story, but you didnt ask me. 我本来会告诉你这个小男孩的故事，但是你没有问我。8.should have done意思是本来应该做某事，而实际没做。shouldnt+have+done表示本来不应该做某事，而实际做了。含有指责对方或自责的含义。Tom, you are too lazy. The work should have been finished yesterday. 汤姆，你太懒惰了，这项工作本来应该昨天就做完的。Look, Tom is crying. I shouldnt have been so harsh on him. 看，汤姆哭了，我本不应该对他如此严厉的。9.ought to have done表示过去应该做而实际并没有做，译成理应做，往往表示遗憾。与should have done用法基本一样。 I ought to have gone home last Sunday. 我理应上星期日回家。You ought not to have given him more help. 你不应该帮助他那么多。10.need have done表示本来需要做某事而实际没有做。neednt have done则表示本来不需要做某事而实际做了I neednt have bought so much wine only five people came. 我本来没有必要买这么多酒，只来了五个人。He need have hurried to the station. In that case, he wouldnt have missed the train. 他本来需要快点去车站的，那样的话，他就不会误了火车。易错点3 虚拟语气时态的误用1. I _ through that bitter period without your generous help.【错因分析】此题考生容易误认为空格处表示现在的情况，用would+动词原形，从而填成了wouldnt go，实际上这是对过去的假设。【试题解析】句意：如果没有你的慷慨帮助我不能度过那段艰难的时期。度过那段艰难的时期是过去发生的事情，因此这里是对过去发生的事情的假设，又因这里表示否定意义，因此要用couldnt have done。【参考答案】couldnt have gone 虚拟语气中，主句用would / might / could + 动词原形表示现在或将来的情况，用would / might / could + have + 过去分词表示过去的情况。1.【2018北京卷单项填空】They might have found a better hotel if they _ a few more kilometers.A. drove B. would drive C. were to drive D. had driven【答案】D2. But for their help, we _ the program in time. A. cannot finish B. will not finish C. had not finished D. could not have finished【试题解析】句意：要不是他们的帮助，我们不会按时完成这个项目。考生容易误选C项，原因是没有注意到but for their help这一含蓄条件。由语境可知，这里表示与过去的事实相反，所以主句应该用would /could / might / should + have done结构。【答案】D【名师点睛】（1）有些句子中，没有任何表示虚拟语气的词、短语或从句，但仍要用虚拟语气。这时，要么是省略了表示虚拟语气的部分，要么是隐含在上下文之中。We would have made a lot of money. 我们本来能够挣很多钱的。（2）用介词代替条件状语从句。常见的介词有：with，without，but for等。But for the rain (=If it had not been for the rain), we would have finished the work. 要不是下雨，我们就完成这项工作了。Without electricity (=If there were no electricity), life would be quite different today. 如果没有电，今天的生活就会是另一个样子。（3）用but，otherwise，or else等由真实语气转化为虚拟语气或反之。The captain kept calm in the terrible storm, otherwise the accident wouldnt have been prevented. 船长在可怕的大风暴中显得很镇静，否则一场事故不可避免。3. It is hard for me to imagine what I would be doing today if I _ in love, at the age of seven, with the Melinda Cox Library in my hometown. A. wouldnt have fallen B. had not fallen C. should fall D. were to fall【答案】B【名师点睛】错综条件句就是虚拟条件主句和从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择适当的动词形式。If I were you, I would not have missed the film last night. 如果我是你，我不会错过昨晚的电影。If they had started in the early morning, they would arrive in half an hour. 如果他们清早就出发，那么再有半个小时就到了。时态类型主句谓语形式条件句的谓语形式例句与现在事实相反would / should / could / might + 动词原形动词过去式did*be 多用wereIf I were you, I should study English.I would certainly go if I had time.与过去事实相反would / should / could / might + have done动词过去完成式had doneIf you had taken my advice, you would not have failed in the test.If I had left a little earlier, I would have caught the train.与将来事实相反would / should / could / might + 动词原形动词过去式If you came tomorrow, we would have the meeting. If it were to rain tomorrow, the meeting would be put off.should + 动词原形were + to do注意：1. would/should/could/might主句谓语中的should主要用于第一人称；would表示结果还表示过去经常做某事，might表示可能性，could表示能力、允许或可能性。比较： If you tried again, you would succeed. 要是你再试一试，你就会成功的。 (would表结果) If you tried again, you might succeed. 要是你再试一试，你可能会成功的。 (might表可能) If you tried again, you could succeed. 要是你再试一试，你就能成功了。(could表能力) 2. 错综时间虚拟条件句 即条件从句与主句所指时间不一致，如从句指过去，而主句即指的是现在或将来，此时应根据具体的语境情况，结合上面提到的三种基本类型对时态作相应的调整： If it had rained last night, the ground would be wet now. 要是昨晚下过雨的话，现在地面就会是湿的。You would be much better now if you had taken my advice. 假若你当时听我的话，你现在就会好多了。 3. If虚拟条件句的否定（含蓄条件句） 常考两个句型：If it werent for.和If it hadnt been for.，其意为若不是(有) 要不是。If it werent for water, no plant could grow. 要是没有水植物就无法生长。 If it hadnt been for your assistance, we wouldnt have succeeded.=But for your assistance, we wouldnt have succeeded.=Without your assistance, we wouldnt have succeeded.要是没有你的支持，我们不会成功的。4. If虚拟条件句的倒装形式，即把were，had，should置于句首。Were I in school again (= If I were in school again), I would study harder. 如果我再上学，我一定更加努力地学习。Had you asked me, I would have told you.=If you had asked me, I would have told you.要是你问我的话，我就告诉你了。易错点4 忽视名词性从句中虚拟语气的用法1. The doctor remended that you _ swim after eating a large meal. A. wouldnt B. couldnt C. neednt D. shouldnt【错因分析】考生容易误选B项，原因是不知道remend的宾语从句中要用虚拟语气。【参考答案】D2. It is important that we _. A. shall close the window before we leave B. will close the window be
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