《高考英语一轮复习之情态动词知识精讲讲义.docx》由会员分享，可在线阅读，更多相关《高考英语一轮复习之情态动词知识精讲讲义.docx（10页珍藏版）》请在taowenge.com淘文阁网|工程机械CAD图纸|机械工程制图|CAD装配图下载|SolidWorks_CaTia_CAD_UG_PROE_设计图分享下载上搜索。
1、高中英语一轮复习之情态动词知识精讲一、情态动词及其否定形式情态动词表示说话人对某动作和状态的态度和意愿,有一定的词意,但不能单独作谓语必须和动词连用,没有人称和数的变化。一、can(could);may,(might); must(一)表能力允许或必须He can see a bird a mile away.(现在)She listened, but she could hear nothing.(过去) You may come at any time you like.May I come in? Yes, you may./ No, you mustnt. May (Can) I sm
2、oke here? Yes, you may (can).We must work hard for our motherland.Must you go so soon? Yes, I must./ No, I neednt.注意:1.could在陈述句中表示过去的能力。在疑问句中表示委婉地提出自己的看法或请求，与 can无时间上的区别，但回答时用现在形式(原形)。类似的还有might,would 等。-Could/Can/ Would / Will you show me that one? -Yes,I can/will.2.在肯定的陈述句中,can,may都可表示“可能，可以”。may
3、表示事实上的可能性，或正在发生或将要发生的具体可能性。 can表示逻辑上的可能性和一般的可能性。 Mary is in poor health. She can be ill.(逻辑) Mary looks pale.She may be ill.(事实)A wise man can make such mistakes sometimes.(逻辑) You may make such mistakes in the test.3. can的否定和肯定不能同时出现在一个句中，但may可以。may一般不用于被动语态。 The thief may or may not come again.4.m
4、ay一般不用二、三人称的疑问句，而can可用于各人称的疑问句,常可用likely或do you think 来表达。Do you think it will rain? Is it likely to rain?5.can 与 be able tocan与could表示能力时，不用be able to;be able to有更多的时态，但can可表示将来，不能用于将来。You can come on Sunday.be able to的否定式一般为be not able to,而不用be unable to。 He was not able to jump across / over the
5、riverbe able to 不能用于被动而can则行。 He can make a beautiful model plane. A beautiful plane can be made by him.be able to用于过去时，表示“设法干成功了，暗示在过去某场合经过努力才具备的能力。He can speak English after two years study.(不用 be able to)Although the pilot was badly hurt he was able to explain what had happened. The fire spread t
6、hrough the hotel very quickly but everyone was able to get out.6.疑问及其肯定与否定回答:can-cant不能;may- may not(语气较强,少用)或 mustnt(常用来表示不可以,不允许);must-neednt(不必),不用 mustnt。-Will you please open the door? -Yes I will./ OK.-Would you please open the door? -Yes I will./ No, I wont.-Could you please open the door? -Y
7、es,I can./ No, I cant. -May I open the door?-Yes, you may./ No, you mustnt -Must I open the door?-Yes, you must./ No, you neednt.7. must, have tomust表示“必须”时，否定neednt或dont/ doesnt / didnt have to 或 havent/ has n hadnt got to d be not obligated to;若表示过去或将来时的必须”，到用have to的适当形式 musn1表示“禁止、不准”因为must无过去式，
8、但must也可用于间接引语或宾语从句中表示过去。His father thought she must have met a fairy He had to go to the hospital yesterday. He told me he must be there.must表示个人的意志和主观上的必要,理论上的论断和自然法则的必要;have to 表示客观上的必要。He has to go to school every day. He must go to school every day.区别:He hasnt got to the school.他还没到学校。 He hasnt
9、got to go to school. 他不必到学校。(二)表推测或判断may(might)通常只用于肯定或否定的陈述句中,can多用于疑问句或否定句中,must 只用于肯定甸的陈述句中。may的可能性最小，must的可能性最大。He may be in the office.Mr Li may / might be in the teachers office.He cant be in the room. I saw him outside just now. How can you be so careless?She must be at home. The light is on.
10、注意:1.must be+v-ing表示目前情况的一种肯定推测,否定用cant。 They must be waiting for us at the station. Its shining. It cant be raining outside.2.must have+过去分词,表示主观上对过去某事的推测,其否定用cant+have+过去分词。 Its very late. They must have slept.Its very early. They cant have gone to bed.二.dare在英语中可作情态动词，也可作实义动词。1作情态动词时无人称和数的变化,有过去式
11、,但少用;后接动词原形,主要用于否定句、疑问句和条件从句中。He dare not / darent tell his father the bad news Dare you touch the wire?If the enemy dare come, they will never get away.2. 作实义动词时有人称和数的变化,接不定式作宾语、在疑问句和否定句中可省略to Did she dare (to) go out at dark night? She dares to go through the forest.3. 当anybody,nobody作主语时,在陈述句中可省略
12、to。 Anybody/ Nobody dares (to) do it.4. I dare say . 我敢说.I dare say there are some mistakes.4. How dare you do sth.表示说话人的一种愤怒。 How dare you say that?How dare you open my letter?三、need1.need作为情态动词时无过去式，并以同一形式用于现在和将来时中，一般仅用于否定句和疑问句中,在肯定句中要用must,have to,ought to,should 代替。We neednt wake up so early, ne
13、ed we? Need we hand in the papers?I dont think you need wear a coat.mustnt表示否定的义务，或说话人强有力的劝告,意为“禁止,不许，不必要”。neednt表示“不必要”,没有义务;同意某一行为可以不履行，有时仅表明某一行为是不必要的。You mustnt tell anyone.(=Dont tell anyone.) Visitors mustnt feed the tigers.You neednt make five copies. One will do.You neednt drive so fast. We h
14、ave plenty of time.2.作实义动词时,有人称和数的变化,意为“需要,必需”。主+谓+宾(名,代,动名词,to不定式)need doing sth.(用主动形式表被动意义) need to be doneWe need (to buy) pens.The desk needs repairing / to be repaired. The old man needs to be looked after.四、would,used to, willwould可指过去习惯的或反复发生的动作，不能表示过去存在的状态。 used to既可指过去反复发生的动作，也可表示过去存在的状态。
15、will可表示现在习惯性的动作或某种倾向。 China is not what it used to be.He used to be a thief.(不能用 would)She would / used to sit under the tree, thinking. The fish will die out of water-Whats the matter with the door? -It wont lock.五、ought to,should1均意为“应该,应当”,ought to 比should 语气强。 You ought to visit your sick friend
16、 more often. -I dont care what people think.-Well, you should.2.ought to无过去式,当用于过去情况时,特别是在宾语从句中,仍用该形式;可用于被动语态中，表示有责任、有义务去做某事。You are his brother. You ought to care for him He ought to be punished.3. should like to do sth.相当于wish或want,但语气更委婉。Id like to go with you. Id like you to go with me.六、情态动词+ha
17、ve+过去分词肯定:表示该做的事而没有做。否定:不该做的事而做了。I.should / ought to +have+过去分词，表示过去该做的事没有做。 We should have given you more help, but we were busy then. You ought to have thought of that, but you didnt.2.shouldnt/oughtnt to/neednt -have+过去分词，表示不该做的却做了,不必做的却做了 You shouldnt / oughtnt to have told him the news. We need
18、nt have told him to go again.3.cant+have+过去分词，表示推测过去不可能发生的事。 They cant / couldnt have finished the work so soon.4.could+have+过去分词，表示过去能做的事而未做。 In these conditions we could have helped more children5. may/might+have+过去分词，表示推测过去某事也许已经发生。 You may / might have read the article in the newspaper. He may /
19、 might not have seen the film.6. might+have+过去分词，也可说明某事过去没有实现，并含有劝告甚至责备之意。 You might have told me earlier七、 情态动词也可和动词的进行时构成谓语,表示“应当正在,想必正在”。 Why should we be sitting here doing nothing? This isnt what I ought to be doing. He cant be swimming today.八、 情态动词与现在完成进行时连用，表示“应当一直在,想必一直在”。 You should have b
20、een waiting for us.He may / might / must / cant have been reading.九、should用于表示惊讶、忧虑惋惜、惊奇遗憾等情绪时意为“竟然会，竟然”;should have done 也可表“竟然已”The painting considered to have copied should have won the first prize. It worries me that he should be so lazy.他竟如此懒，真让我担心。You cant imagine that a well-behaved gentleman
21、 should be so rude to a lady十、shall 用于二、三人称表示“强制、命令、允诺、威胁”等。 You shall finish the work before 5 oclock. He shall have the book as soon as I finish it十一、shall用于一三人称可用于征求对方意见或请求对方给予指示。1.-Shall Tom come in. sir? -Yes, please.2.-We need a person badly to think up such an idea.-Shall the newcomer have a
22、try? / Shall I help you with the work?十情态动词的一些惯用法1.cant/couldnt+比较级“再不过,不可能更 I cant agree more.我完全同意。He couldnt have done better.他做得再好不过了。2. cannot . too/enough表示“无论怎么也不过分，越越好”。如You cannot be too careful. 你越小心越好。You cannot remember enough English words.你记的英语单词越多越好。3. cannot but do sth.表示“不得不,只好”。I c
23、annot but admire your bravery. 我不得不钦佩你的勇气。 I could not but choose to go.我只好去。4. may well 和 may as well 结 构“may well+动词原形”是一种常用结构,意为“完全能,很可能”,相当于to be very likely to。如:He may well be proud of his son.他大可为儿子感到自豪。Her appearance has changed so much that you may well not recognize her.她的模样变化太大,你很可能认不出她了。“may as well+动词原形”意为“最好,蛮可以,倒不如”,相当于had better 或 to have no strong reason not to。如:You may as well stay here over the night. 你最好留在这里过夜。 You may as well do it at once, 你最好马上就做这件事。We may as well stay where we are. 我们留在现在的地方倒也不错。 You may as well tell me the truth.你还是把真相告诉我的好。学科网（北京）股份有限公司学科网（北京）股份有限公司