情态动词的用法.docx

1、情态动词的用法课题名称情态动词的用法教学目标同步教学知识内容情态动词的用法个性化学习问题解决情态动词的运用教学重点情态动词的运用教学难点can，must，may的异同点教学内容一、情态动词的概念 情态动词是一种本身有一定的词义，表示说话人的情绪，态度或语气的动词，但不能单独作谓语，只能和其他动词原形构成谓语。 We can be there on time tomorrow.我们明天能按时去那儿。 May I have your name? 我能知道你的名字吗？ Shall we begin now?我们现在就开始吗？ You must obey the school rules.你必须遵守校

2、规。情态动词数量不多，但用途广泛，主要有下列： can (could), may (might), must, need, ought to, dare (dared), shall (should), will (would), have (to), had better. 二、情态动词的用法常用的情态动词有can，may，must，need,should, had better.（一） can 的用法： 1. 表示能力 “能，会” eg: He can speak a little Japanese.他会说一点日语。 We can be there on time tomorrow. 我们

3、明天能按时去那儿。 2. 表示请求或允许“可以” eg: Can I help you? 要我帮忙吗? 3. 表示猜测“可能” eg: Where can she go now? 她可能到哪里去了呢? He can be at home now. 他现在可能在家。 The moon cant always be full. 月亮不可能常圆。注意： could也可表示请求，语气委婉，主要用于疑问句，不可用于肯定句，答语应用can（即could不能用于现在时态的简略答语中）。如： Could I come to see you tomorrow? 我明天能来看您吗？ Yes, you can. （

4、否定答语可用No, Im afraid not.） 是的，你可以。（不，恐怕不行。） （二）may 的用法：1.表示请求或允许“可以”“准许” eg: May I go home，please? 请问我可以回家吗? You may go now. 你可以走了。2.表示可能性“ 可能”、也许”eg: I think it may rain this afternoon. 我想今天下午可能下雨。 You may be right. 你可能是对的。 注：might为may的过去式，但也可以代替may，语气较为婉转客气或更加不肯定。 eg: He might not come today.今天他也许不

5、来了。(语气不肯定) You might also get a headache when you work too hard. 当你工作太努力时，你也可能患头痛。注意：以may（表许可或请求）开头的一般疑问句的肯定回答用may，否定回答用mustnt或cant。（三） must的用法： 1.表示义务、必要或命令“必须、应该” eg: You must come early tomorrow你明天得早来。 2. 表示推测时“肯定，一定”eg: They must be at home.The light is on. 他们肯定在家,灯亮着呢. 3. must not禁止，不许 eg: You

6、must not tell lies. 你不许撒谎。 注意：must开头的疑问句，其否定回答通常用 dont have to 或neednt。而不用mustnt eg: -Must I finish my homework first? 我必须先完成作业吗？-No, you dont have to/ neednt. 不，你不必。 can和must在表推测时，can一般否定句中，而must 常用于肯定句中。eg: It can not be Li Lei 那个人不可能是李磊 It must be Li Lei 那个人肯定是李磊。情态动词表推测的用法小结&横向分析1、表示“能力”。 (1)只可用

7、can（could）。may、must则无此种含义。 例：I can swim now，but I couldnt last year. Can you play me piano？Yes，I can (2）can（could）适用于各种句型和人称。 例：肯定句：I（You，He）can swim. 否定句：I（You，He）cant swim. 疑问句：Can I（you，he）swim？2、表示“请求”或“许可”。can、may、must都可用，但语气和程度不同。(1)can（could）用于各种句型和大部分人称。 例：肯定句：You（He，We）can go now 否定句：You（He

8、，We）cant go now 疑问句：Can I（you，he）go now？ -Yes，you can（No，you cant）(2)may（might）用于各种句型，但在肯定句和否定句中不用于第一人称；在疑问句中不用于第二人称。 例：肯定句：You（He）may go now 否定句：You（He）may not go now 疑问句：May I（he）go now？ （肯定）Yes，you may （否定）No，you may not（No，you cantNo，you mustnt）(3)must用于各种句型和大部分人称。 例：肯定句：I（You，He）must go now 否定句

9、：You（He）mustnt go now 疑问句：Must（you，he）go now？ 肯定回答：Yes，you must. 否定回答：No，you neednt（No，you dont have to）(4)试比较： You may not smoke here（不可以）语气轻 You cant smoke here（不能）重 You mustnt smoke here（决不可）最重3、表示“可能”、“或许”和“推测”之意。can、may、must都可用，但语气和程度不同。(l)can（could）常用于否定句和疑问句中，could表示的“可能性”更小。 例：否定句：It couldnt

10、 be him，for hes at the library 疑问句：Can he have gone out？ What can they be doing now？(2)may（might）用于肯定句和否定句中，might表示的“可能性”更小。例：肯定句：He may be right 否定句：She might not have come yet(3)must用于肯定句中。 例：You must be very hungry（对现在情况猜测） Aqiao must have met a fairy（对过去事实的猜测） Everything is clean and tidySomeone

11、 must have cleaned my room（同上）(4)试比较： He might not have gone out（或许没有） He cant have gone out（不可能） He must have been in the room（一定、准是） 以上三句可能性逐渐加大至肯定。4、情态动词表推测的三种句式（1）在肯定句中一般用must （一定），can,could（可能），might /may（也许，或许）。肯定句中表推测“可能”：can,could,may,might都可以在肯定句中表“可能”。其中can的语气最强，可能性最大，其余依次递减。 肯定句中表推测“一定，肯定

12、”用must.He must/can/may,might know the answer to this question. 他一定/可能/也许知道这个问题的答案。It is cold in the room. They must have turned off the heating. 屋里很冷，他们肯定把暖气关了。（2）否定句中用cant / couldnt（不可能），may not/might not（可能不）。.否定句中表推测： may not/might not：可能不；can not/could not： 不可能 eg: 、You may not be right你也许不对. 、Y

13、ou can not be right你不可能对. 、It cant/couldnt be the headmaster. He has gone to America. 这不可能是校长，他去美国了。 、He may not/might not know the scientist. 他也许不认识那位科学家。（3）疑问句中用can/could （能?）。疑问句中表推测“可能”：用can,could,might,而不能用may. mustnt 不表示推测，而表示禁止。 意义为“禁止，不准”Could he have finished the task? 他可能把任务完成了吗？Can he be

14、at home now? 他现在能在家吗？ 注：以上三种句式中情态动词的语气按程度都是依次递减的。Might,could并非may,can的过去式，而表示语气较为委婉或可能性较小。（四）. need 的用法： 1. 情态动词“需要, 有必要”一般用于否定句或疑问句中。 eg: You neednt come here this afternoon. 你今天下午不必来。 2. 行为动词 “需要, 有必要” 可以用于各种句式中。象其他动词一样，有第三人称，单复数，后面加带 to 的动词等特性。eg: You dont need to go now. 你不必现在就走。 I need to have

15、a rest. 我需要休息一下 Do we need to finish all the work today? 我们今天需要完成所有的工作吗？need的用法的助记口诀：实义动词表“需要”，后接名、代、不定式。need后接动名词，主动形式表被动。情态动词表“需要”，没有人称 数之变。其后直接加动原，多用疑问与否定。（五）. should1.表示说话人的猜测，估计应该That should be Janet coming upstairs now. 正在上楼的准是珍妮特。2表示劝告或建议。例如： He should learn how to drive the car. （六）. had bet

16、terhad better(常简略为d better)是一固定词组，had better最好，用于表示对别人的劝告、建议或表示一种愿望。其用法有以下几点：1. had better后面必须跟动词原形。had better后跟动词原形(即不带to的不定式)，构成had better do sth.句型。这里的had不能用have来替换。如：Youd better go to hospital at once. 你最好立即去医院看病。Tom, youd better go there today. 汤姆，你最好今天去那儿。2. 主语不论是第几人称，句子不论是什么时态，都要用had better的形

17、式。如：Now you(he，we) had better listen to the teacher. 你(他，我们)现在最好听老师讲。（七）. shall和should的用法1.Shall的用法： . Shall用于第一人称，表示征求对方的意愿。如： What shall we do this evening? . Shall用于第一、第三人称疑问句中，表示说话人征求对方的意见或向对方请示。如： Shall we begin our lesson? When shall he be able to leave the hospital? . Shall用于第二、第三人称，表示说话人给对方命

18、令、警告、允诺或威胁。如： You shall fail if you dont work harder. （警告） He shall have the book when I finish reading. （允诺） He shall be punished. （威胁） （八）. will和would的用法1. 表示请求、建议等，would比will委婉客气。如： Would you pass me the book? 2. 表示意志、愿望和决心。如： I will never do that again. They asked if we would do that again. The

19、door wont open. 三、情态动词练习1May I stop my car here? No, you .A. cant B. mustnt C. neednt D. dont have to2. Must we clean the house now? -No, you _.A. neednt B. may not C. mustnt D. cant3. When he leave the hospital? I asked the doctor.A. will B. shall C. can D. may4. You return the book now. You can ke

20、ep it next week if you like.A. cant B. mustnt C. neednt D. may not5. Johnny, you play with the knife, you hurt yourself.A. wont.cant B. mustnt.mayC. shouldnt, must D. cant.shouldnt6. Must we come tomorrow? - . .A. No, you cant B. No, you needntC. No, you mustnt D. No, you may not7. Would you go out

21、for a walk with me?No, I . My girl friend is coming.A. wouldnt B. shall not C. wont D. shouldnt8. Man die without water.A. will B. can C. need D. shall9. You miss the lesson, though we have it on Thursday.A. mustnt.neednt B. neednt.mustntC. mustnt.mustnt D. neednt.neednt10. I mailed the letter two w

22、eeks ago. She_it.A. must receive B. cant receive C. might receive D. must have received11.The professor gave orders that the experiment before 5:30p.m.A. be finished B. will finishC. must be finished D. would be finished12. There was plenty of time. You .A. mustnt hurry B. mustnt have hurriedC. need

23、nt hurry D. neednt have hurried13. Tom was a diligent boy. He go to school though it was raining hard.A.was able to B. could C. couldnt D. wasnt able to 14. I go back before lunch?No, I dont think you .A. Need.must B. Do.need to C. Must.have to D. May . ought to15. The teacher do all the exercises,

24、but a pupil .A. neednt.must B. may not.mustC. neednt.neednt D. cant.must16. Would you open the window please ?Yes, I .A. will B. would C. do D. can17. A lion only attacks a human being when it is hungry.A. should B. can C. will D. shall18. -Must I finish this novel this morning ?-No, you_.A. mustnt

25、B. might not C. dont have to D. cant19. The taxi only hold six passengers. It is full. You take the next one.A. may.may B. can.may C. may.can D. must.can20. I a little earlier, but I met a friend of mine on the way.A. may come B. may have come C. could have come D. must have come21. I wish to go hom

26、e now, I?A. may B. cant C. must D. do22. He must have finished his homework, he?A. mustnt B. didnt C. neednt D. hasnt23. This pen looks like mine, yet it isnt. Whose it be?A.must B. can C. may D. might24. He didnt do well in the exam. He hard at his lessons.A. must have worked B. ought to have worke

27、dC. would have worked D. has worked25. Would you come and join them?I wish I . But I am busy at this moment.A. cant B. couldnt C. could D. can26. Mr Baker, a number of students want to see you. they wait here or outside?A. Should B. Will C. Shall D. Are27. You the trees. Look, it is raining now.A. m

28、ustnt have watered B. neednt have wateredC. could have watered D. might have watered28. I give you an answer tomorrow. I promise!A. must B. will C. may D. shall29. As a soldier, you do as the head tells you.A. will B. shall C. may D. ought30. The streets are all dry. It during the night.A. cant have rained B. must have rainedC. couldnt rain D. shouldnt have rained