高考英语情态动词与虚拟语气

1、高考英语-情态动词与虚拟语气 情态动词与虚拟语气情态动词(Modal Verbs)1情态动词记忆口诀情态动词二要点：动词原形跟后面，说话语气委婉。can表“能力”may“许可”，must“责任”或“义务”，否定回答needn't换；“需要”need、dare“敢”，should“应该”、would“愿”，have to“被迫”表客观。说明：情态动词：can(could)、may(might)、must(must)、need、dare、will(would)、shall(should)等。对must构成的一般疑问句作否定回答只能用neednt。dare和need一般在疑问句或否定

2、句中作情态动词，而肯定句中作行为动词。2may, can和must的否定式may常表示“许可”和“可能”People may not pick flowers in this park.Borrowers may not take out of the library more than two books at a time.有时may not可以由must not替换，且must not更为普通。That may not be true.=It is possible that that is not true.He may not be serious.一、can通常表示“能力(abil

3、ity, power, capacity)”、“允许(permission)”、“可能(possibility)”。1can表示“能力”时，它的否定式表示客观上或主观上没有这种能力。如：He cant speak English.I can come to your party, but Alice cant, shes got to go to a meeting.当can与表示感觉和心理状态的动词(see, hear, understand等)连用时，往往失去情态意义。如：I cant understand why he was so angry.此句中的cant understand实际

4、上等于dont understand, can失去了它原有的情态意义。2can表示“允许”时，它的否定式表示“不允许”、“禁止(prohibition)”。这种用法和表示“禁止”意义的may not, must not同义。如：You cant (mustnt, may not) play football in the park on Sundays, though you may do so on weekdays.3can表示“可能”时，它的否定式表示“不可能(impossible)”。It cant be true. = Its impossible that it is true.二

5、、must通常表示“必须(suggesting a command or an obligation)”、“必然、肯定”的推测(a logical conclusion, a strong likelihood)。1must表示“必须”时，它的否定式neednt表示“不必(dont have to)”；它的否定式must not表示“不许可”或“禁止某人做某事”，同may not(1)及can not (2)同义。如：You neednt hand in your composition at once.Cars mustnt be parked in front of the house.2

6、must表示“必然”和“肯定推测”时，没有否定式；它的否定意义由can not表示。If Tom left here at six oclock, he must be home by now.If Tom didnt leave till six oclock, he cant be home yet.3怎样 选用can和may情态动词can和may都能表示“可能性”。如(1)He may be right.他可能对。(2)He cant be right. 他可能不对。那么，在表示可能性这个概念时，二者的区别是什么呢？I二者所适用的句子类型不同。一般说来，can多用于疑问句和否定句，表示怀

7、疑或不相信等态度；而may则多用于陈述句(肯定)，表示一种揣测。如：Can it be true? No, it can not be true.这可能是真的吗？不，决不可能是真的。Where can they be now?他们现在可能在哪里呢？I hear there may be a few copies left.我听说可能还剩下几本。What he said may not be right.他说的可能不对。二者所强调的意思不同。一般来说，can强调客观上的可能性，而may则强调主观上的推测或判断。如：Man can not live without air or water.没有空

8、气和水人就不能生存。She may be in the library, I suppose.我想她也许在图书馆里。She may not be there today.今天她可能不在那儿。二者表示的语气不同。在否定句中，can表达的否定语气较强，意为“不可能”；而may表达的否定语气较弱，意为“可能不”或“也许不”。如：That can not be true. (=It is impossible that is true.)那不可能对。That may not be true. (= It is possible that that is not true.)那也许不对。根据以上分析，我

9、们可以归纳为三条原则：在肯定句中用may不用can；在疑问句中用can不用may;在否定句中，若语气肯定，表示“不可能”时用can not，若语气不肯定，表示“可能不”时用may not。三、need用法歌诀(一)实义动词表“需要”，后接名、代、不定式。need后接动名词，主动形式被动意思。(二)情态动词表“需要”，没有时态数人称，其后直接跟动词，多用于疑问和否定。(三)名词need表“需要”，初中用得比较少。need词性共三种，用时千万要慎重。说明：实义动词need，表示“需要”的意思，其后可以跟名词、代词和动词不定式作宾语。如：We need it very much. (need代词)H

10、e needs some help.( need名词)He needs to have a long rest.( need不定式)need后接动名词，是主动形式表达被动意思。如：The room needs cleaning. 那房间需要打扫。The car needs mending. 车子需要修理。情态动词need表示“需要”的意思，没有人称、数和时态的变化，其后可以直接跟动词原形， 但这种句法多用于疑问句和否定句。如：Needwe buy five new bikes?No, we neednt. (或Yes, we must.)在交际用语中，许多同学对need的以上两词性易混淆，把握

11、不准，试比较，请找出规律来。Need he go now? (情态动词)Does he need to go now?(实义动词)need也可以作名词表“需要”，但初中教材中出现的次数较少。如：He told Dr. Bethune that the front was in great need of medical workers.他告诉白求恩大夫说前线非常需要医务工作者。四、巧记表“推测”的情态动词用法表“推测”时，情态动词可用can, could, may, might, must。must表“一定”，只用于肯定句，其否定形式要用cant; may(might)表“或许”，可能性较小，

12、不用于疑问句；can表“可能”，不用于肯定句。为方便记忆，可用一句话来记忆，即：肯(can)不能？妹(may)不问，妈妈(must)肯定不否问。“肯(can)不肯”即can不用于肯定句；“妹(may)不问”即may不用于疑问句；“妈妈(must)肯定不否问”即must只用于肯定句，而不用于否定句和疑问句中。五、浅谈“情态动词have过去分词”结构情态动词must, may, might, can, could, need等后接不定式完成式，可以表示说话人对一个已经完成了的动作或已发生了的事的推断或揣测，所表示的含义各不相同。1must have done 过去一定/必定cant/ couldn

13、thave done 过去不可能neednt have done 本来不必The streets are wet, it must have rained last night.The light is still on; he cant have gone to sleep.You neednt have come over yourself.2may/mighthave done 可能may/might nothave done 可能不会He might have arrived there by now.He might not have settled the question.3sh

14、ouldhave过去分词这一结构表示过去该做而实际上未做的行为动作，意思是“本应该”。其否定式为“should nothave过去分词”，表示不应该发生的行为，意思是“本不应该”。其同义结构为“ought tohave过去分词”，表示过去“早应该”、“本当”之意，语气较强。如：You should have come here five minutes earlier.你应该早来五分钟才是。(实际上未做到)You should not have gone to watch TV. You are going to take an examination in English tomorrow.

15、你不应该去看电视，你明天还要参加英语考试呢。(实际上已经看了)We ought to have given you more help.我们本应该给你更多的帮助。(实际上未做)She ought not to have stopped her work half way.她不应该将工作做了一半就停下来。(实际上 已停了下来)4will(would)have过去分词这一结构表示对过去发生的行为进行推测，其含义为“大概”、“猜测或料想”等意思，它与“will动词原形”有区别。“will动词原形”是表示现在的推测或表示将来肯定会取得某种结果。如：He will have gone back to N

16、anjing.他大概已经回到南京了吧。This will be the house youre looking for.这大概就是你要找的那间房子。5can(could)have过去分词Can you have done the exercises?你会做完练习吗？They cant have finished the work so soon.他们不可能这么快就做完了。虚拟语气(Subjunctive Mood)一、虚拟语气用于条件状语从句1表示与现在事实相反的假设时，条件状语从句的谓语动词用“过去式(be的过去式用were)”，而主句中的谓语动词用“would (should, could

17、, might)动词原形。”2表示与过去的事实相反的假设时，条件状语从句的谓语动词用“had过去分词”，主句中的谓语动词用“would ( should, could, might)have过去分词”。3表示与将来事实相反的假设时，条件从句和主句所用的谓语动词与“表示与现在事实相反的假设”的谓语动词相同，或者条件从句中用“were to ( should)动词原形”。综上所述即可，以下表归纳：以动词do为例：If-clauseMain clausedid ( present )would / should / could / might dohad done (past)would/ shou

18、ld / could / might have doneshould /were to do / did (future)would/ should/ could / might do4不定式的完成时可表达与过去事实相反假设。例如：To have studied harder, you would have passed the exam.5当条件状语从句表示的行为和主句表示的行为所发生的时间不一致时，动词的形式要根据它所表示的时间来调整。例如：If you had worked hard, you would be very tired.(从句说的是过去，主句说的是现在)6以上句型可以转换成

19、下列形式：省略if，用“were, had, should主语”。Were I in school again, I would work harderHad you been here earlier, you would have seen him.Should there be a meeting tomorrow, I would come.但在虚拟条件状语从句中，省略连词的倒装形式的句首不能用动词的缩略形式。可以说： Were it not for the expense, I would go to Italy.但不能说：Werent it for the expense, I w

20、ould go to Italy. 二、虚拟语气用于宾语从句1“wish宾语从句”表示不能实现的愿望，汉语中可译为“可惜”，“说好了”，“悔不该”，“但愿”等。表示现 在不能实现的愿望，从句的谓语动词用过去式；表示将来不能实现的愿望用“would (could)动词原形”；表示过去不能实现的愿望时用“had过去分词”或“(could) would have 过去分词”。2虚拟语气在某种欲望的动词 arrange, command, demand, desire, insist, order, propose, request, require, suggest, advise, prefer,

21、 agree, expect, intend, recommend, ask, decide, object, persist, determine等后面的宾语从句中用“(should)动词原形”。We suggested that we (should) have a meeting.We insisted that they (should) go with us.The doctor ordered that she (should ) stay in bed for a few days.He demanded that we (should ) start right away.三、

22、虚拟语气用于表语从句、同位语从句作advice, idea, order, demand, plan, proposal, suggestion, request等名词的表语从句和同位语从句，其谓语动词要用虚拟语气的结构“(should)动词原形”。例如：We all agreed to his suggestion that we (should) go to Beijing for sightseeing.My idea is that we (should) do exercises first.四、虚拟语气在as if (as though ), even if (even thoug

23、h)等引导的表语从句或状语从句中的应用。如果从句表示的动作发生在过去，用过去完成时；指现在状况，则用过去时；指将来则用过去将来时，例如：He looked as if he were an artist.He speaks English so fluently as if he had studied English in England.Even if he were here, he could not solve the problem.五、虚拟语气用于主语从句在主语从句中，谓语动词的虚拟语气结构用“should动词原形”的结构，表示惊奇、不相信、惋惜、理应如此等。例如：It is n

24、ecessary (important, natural, strange, essential, urgent(紧急的), surprising, etc) that we should clean the room every day.It was a pity (a shame, no wonder, etc) that you should be so careless.It will be desired (suggested, decided, ordered , requested, proposed, etc) that she should finish her homewo

25、rk this afternoon.在上述三种主语从句中，should意为“应该”，“竟然”，可以省去, 但不可换用would。主句所用动词的时态不限。注意：这种从句表示的是事实。如果说话人对这种事实表现出惊奇的情感，就可用虚拟语气。反之，如果不表示惊奇等情感，that从句也可用陈述语气。例如：It is a strange that he did not come yesterday.It is a pity that you cant swim.六、虚拟语气用于定语从句这种从句常用在It is (high) time (that) 句型中，定语从句的谓语动词用过去式，或should动词原形

26、(should不能省略，be用were)来表示，意为“(现在)该 ”。例如：It is (high) time we left (should leave).It is high time we were going.七、虚拟语气用于If / If only / Oh, that/ Would (that) /Would to God(that)/ wish to God(that)/Wish to Heaven (that)等主语的句中, 其后的宾语也分为现在时, be were, dodid; 过去时, had p. p. ;将来时,would/should/could 动词原形。如：Wo

27、uld that I were young again! 我要是能返老还童就好了！If only I knew the answer!我要是知道答案就好了！If only I hadnt lost it !我要是没丢就好了！If only the rain would stop!雨要是能停就好了！Would to God he would return safely.但愿他平安归来。高考典型例题解析1Are you coming to Jeffs party? Im not sure. I _ go the concert instead.(NMET2000)AmustBwouldCshoul

28、dDmight答案：D解析：might表“可能性”。2I was really anxious about you. You _ home without a word. (NMET2001)Amustnt leaveBshouldnt have leftCcouldnt have left Dneednt leave答案：B解析：表示与过去事实相反的虚拟语气。3Is John coming by train? He should, but he _ not. He likes driving his car. (NMET2002)AmustBcanCneedDmay答案：D解析：本题考察情态

29、动词的用法。先确定问句为将来时态，因为像come, go, leave, start等这类趋向动词的进行时表示将来时。这是至关重要的，因为答语是就一将来的动作作出判断的。先删A项，must not译为“不准”，与句意不合；再排除B项，至少cannot不可分开写；最后排除C项，need not译为“不必”，与句意相左；只有选D项，译为“不可能，不一定”，正好与后文的He likes driving his car.相吻合，故应选D项。4A left-luggage office is a place where bags _ be left for a short time, especiall

30、y at a railway station.AshouldBcanCmustDwill答案：B解析：本题考查情态动词的用法。should应该；can能够，会，可以；must必须；will愿意。题意为“行李寄存处是能够暂时存放行李的地方，尤其是在火车站。”此处用can表示“可以、能够”，故答案为B。5You _ be tired youve only been working for an hour. (NMET2000)Amust notBwontCcantDmay not答案：C解析：本题考查情态动词。句中破折号后的内容对前一句进行解释说明：你只工作了一个小时，所以你不可 能累的。表否定推

31、测时用cant。A项表禁止(不许)，B项表未来，D项表不允许。均不可用，故选C。6I often see lights in that empty house. Do you think I _ report it to the police? (NMET2004)AshouldBmayCwillDcan答案：A解析：本题考察情态动词。在空房子里看到灯光，是一件奇怪而令人生疑的事，故问：你是否认为我应当把这事儿报告给警察？所以A。7Mr. White _ at 8:30 for the meeting, but he didnt show up. (NMET 2004)Ashould have

32、 arrivedBshould arriveCshould have had arrivedDshould be arriving答案：A解析：本题考虚拟语气及责备的用法。全句意为：Mr. White (原本)8：30应该到会的，但他没露面。全句谈的是过去的事，故应使用should have done结构，表示原本该做而没做的事。8Tom graduated from college at a very young age. Oh, he _ have been a very smart boy then.AcouldBshouldCmightDmust答案：D解析：本题考查情态动词的用法，m

33、ust用于肯定句表示推测。9I dont mind telling you what I know.You _. Im not asking you for it. (2004, 江苏)AmustntBmay notCcantDneednt答案：D解析：考情态动词。前句话说：我不介意告诉你我所知道的事。后句说：你没有必要告诉我，我并没有向你问此事。此时说没有必要，不表禁止，所以选D。10Who is the girl standing over there?Well, if you _ know, her name is Mabel.(2004，天津)AmayBcanCmust Dshall答

34、案：C解析：本题考查情态动词，答语意思是：“如果你一定要知道的话，(我就告诉你吧)她的名字是Mabel。”故选C。A、B和D项分别表示“可以”、“能够”、“应该”，不合句意。11Children under 12 years of age in that country _ be under adult supervision when in a public library.AmustBmayCcan Dneed答案：A解析：此题从所给的选项中的几个情态动词的意义就可先排除may和can，他们的意义为可以、可能、能够，而need做为情态动词，只能用于否定句或疑问句，做为实义动词后接动词不定式，选A正取must表“必须”之意。12“The interest _ be divided into five parts, according to the agreement made by both sides,”declared the judge