高中英语情态动词讲解

1、Grammar: How many modal verbs do you know?can couldmay mightshall shouldmust will wouldought tohave to dare (darent)need (neednt) used to表示推测表示推测不表示推测不表示推测modal verbs表示推测表示推测一定，肯定一定，肯定 must一定不，不可能一定不，不可能cant, couldnt可能肯定句可能肯定句 may ,might ,could否定句否定句 may /might not疑问句疑问句 can ,could 都可以都可以 + do sth.表

2、示现在表示现在 be doing 表示正在发生的动作表示正在发生的动作 have done表示过去发生的动作表示过去发生的动作He must have a car now.must表示推测时，可以推测现在表示推测时，可以推测现在/正在发生正在发生的动作的动作/过去发生的动作。过去发生的动作。他一定有一辆车他一定有一辆车他一定在教室里做练习。他一定在教室里做练习。 他一定已完成了工作他一定已完成了工作He must have finished the work.He must be doing his exercises in the classroom.一定不，不可能一定不，不可能 cant

3、couldntHe cant be at home. He couldnt have said such a thing .他们一定不在图书馆读书。他们一定不在图书馆读书。约翰是很聪明的，他一定不会叫他儿子那约翰是很聪明的，他一定不会叫他儿子那样做。样做。 They cant be reading in the libraryJohn is very clever . He cannot have told his son to do that .可能可能肯定句肯定句 may ,might，could否定句否定句may might not（可能不）（可能不）疑问句疑问句 can ,couldv

4、他可能正在睡觉。他可能正在睡觉。These students may / might have seen the film before.否定句否定句The boy may / might not be watching TV at home. （现在）（现在）这个男孩可能没在家看电视这个男孩可能没在家看电视He may / might be sleeping nowv疑问句疑问句 How could he have forgotten such an important thing?这么重要的事他怎么能忘这么重要的事他怎么能忘了呢？了呢？ Its so late. Where can she

5、 have gone? 天晚了，她可能去哪儿了呢？天晚了，她可能去哪儿了呢？ Can you have left the watch at home?你你会不会把表丢在家里呢？会不会把表丢在家里呢？1 1Choose the best answers to complete the Choose the best answers to complete the following sentences:following sentences: 1. That man must be Sarahs husband.-No, he_ be her husband. She is still sing

6、le.A. cant B. mustnt C. may not D. ought to 2. Peter _come with us tonight, but he isnt very sure.A. must B. may C. can D. will 3.What_ it be? -It_ be a mail box, for it is moving. It_ be a car. A. can; cant; must B. can; can; must C. can; mustnt; must D. must; mustnt; can 4. Look, someone is coming

7、. Guess_ . -Jack. Hes always on time. A. who can it be B. who he may C. who he can be D. who it can be 5. I saw Mary in the library yesterday.-You_ her. She is still abroad.A. mustnt see B. cant have seen C. mustnt have seen D. couldnt see 6. David, you _play with the valuable bottle, you_ break it.

8、A. wont; cant B. mustnt; mayC. shouldnt; must D. cant; shouldnt 表示能力表示能力一表示能力一表示能力can, could, be able to can表示智力，体力方面的能力只能用表示智力，体力方面的能力只能用 现在现在或过去时。或过去时。 be able to通过努力克服困难作成事情通过努力克服困难作成事情, 能用能用于各种时态。于各种时态。 *was / were able to : 设法做成某事设法做成某事 相当于相当于 managed to do sth. succeeded in doing sth.。vcan与与be

9、 able to 用法区别常与句子时态有用法区别常与句子时态有关关v 1.现在时比较现在时比较v1) 表示表示”能力能力”时时,be able to 不用于第二人不用于第二人称称,v You are able to do the work, I think. (X) 改用改用canvcan与感官动词与感官动词feel, hear, see, smell, taste连用时连用时, can显得可有可无显得可有可无,因而失去了情态动因而失去了情态动词的意义词的意义,这种情况下这种情况下can不能用不能用be able to 代替代替ve.g., We can see beautiful flowe

10、rs and green trees here and there.vAnyone can see it is of no use.3) can) can与某些表示意念的动词如：与某些表示意念的动词如：understand, understand, remember, forget, hope, imagine, believe, remember, forget, hope, imagine, believe, supposesuppose等连用时，同样没有情态动词的意义，也等连用时，同样没有情态动词的意义，也不可用不可用be able tobe able to取代取代。e.g. I can

11、t believe there are so many I cant believe there are so many tall buildings now in my home town tall buildings now in my home town v v2.过去时比较过去时比较was/were able to 意含意含”经过努力经过努力” “凭借才能凭借才能” 获得的获得的”能力能力”常与常与”manage to ”相通相通 They were short of modern machines, but they were able to complete the project

12、 in time. 二表示允许vcan, could ,may, might might,could 表达更客气、委婉、礼貌的请求语气。表达更客气、委婉、礼貌的请求语气。Excuse me, could you tell me the way to the bus station?Could you help me?You can go now if you like.May I smoke in the room?三表示必须三表示必须ought to/should have to must *have to 能用于各种时态能用于各种时态,且有人称和数的变且有人称和数的变化化. ought t

13、o 的否定式为的否定式为ought notto1.should 和和ought tov大多数情况下，含义基本相同，大多数情况下，含义基本相同，should主要主要看主观看法，看主观看法，ought to更多反映客观情况，更多反映客观情况，在谈到法律，规定，义务时使用。在谈到法律，规定，义务时使用。如：如：you should try your best to pass the entrance examinations. We ought to go and see Hellen, but I think we have no time.vShould 还可以表示惊讶，出乎意料的意思还可以表示

14、惊讶，出乎意料的意思 Why should he do such a thing?2.must与与have to 的用法的用法v前者侧重于前者侧重于主观主观意念意念,后者则用于表示后者则用于表示客观客观条件或义务条件或义务,译为译为”只好只好” “不得不不得不”vmust用于用于疑问句疑问句，表示责备、抱怨的感情色彩，表示责备、抱怨的感情色彩，v意思为意思为“偏要偏要，硬要、干嘛，硬要、干嘛”； He must work to make his living. He has to beg for a living.Must没有没有过去式过去式,在单句中若是过去时在单句中若是过去时,须用须用ha

15、d to e.g., He begged from door to door, for he had to do so to live若在从句中若在从句中,则可用则可用must来表示过去来表示过去e.g., He said he must manage to own a new house for Easter. 四表示虚拟should have done 本应该做（而没做）本应该做（而没做） should not have done 本不应该做本不应该做 He shouldnt have said such a thing .他当时不他当时不应该说那种话。应该说那种话。 We should

16、have studied last night, but we went to the concert instead 这种句式也能用这种句式也能用ought toneed not have done没有必要做某事没有必要做某事I need not have got up so early . 我本来我本来不必要那么早起床的（事实上早已起床）不必要那么早起床的（事实上早已起床）I need not have waited for the train for an hour. 我本来不必要等一个小时的火车。我本来不必要等一个小时的火车。（事实上已经等了一个小时）（事实上已经等了一个小时）3. c

17、ould have done它表示它表示“过去本来能够过去本来能够” 实际上没能做实际上没能做。 If you could have finished the task in time，you could have been promoted. 如如果你当时能如期完成那任务的话，你可能已果你当时能如期完成那任务的话，你可能已提升了（实际上没有被提升）提升了（实际上没有被提升） I could have laughed to hear him talk like that.听他那样讲话，我差点笑出声来。听他那样讲话，我差点笑出声来。v4.might have done虚拟式表示与过去事实虚拟式表

18、示与过去事实相反的假没结果。相反的假没结果。 If she had started a little earlier， she might have been in time for the train.如果如果她早点出发，她有可能及时赶上火车。她早点出发，她有可能及时赶上火车。(实际实际上没有早出发，便没有赶上火车上没有早出发，便没有赶上火车) It might have been better to stop then.如果那时就停止的话，也许比较好。如果那时就停止的话，也许比较好。5would have done v它表示的是与过去事实相反之假设的结果，它表示的是与过去事实相反之假设的结

19、果，意思是意思是“当时就会当时就会了了”而实际上没有而实际上没有 I would have helped you if I had known of your difficulties . If it hadnt rained yesterday, we would have gone climbing .假如昨天没下雨，我假如昨天没下雨，我们就去了。（实际上没有去）。们就去了。（实际上没有去）。五其他情态动词用法五其他情态动词用法情态动词情态动词dare, need 通常用于否定句或疑问句通常用于否定句或疑问句 Who dare do it? Dare you go out alone ?d

20、are, need 还可用作行为动词，可以用于各还可用作行为动词，可以用于各种句式，后面可跟加种句式，后面可跟加to的不定式的不定式 A. who dare do it? B. He dares to do it.A. He neednt do it B. he needs to do it 上述句子中A句为含情态动词的句子，B句中dare. need 均为行为动词 注意动词注意动词 dare 的某些特殊用法。的某些特殊用法。1）固定句型固定句型I dare say. 我敢说我猜想以为我敢说我猜想以为 Dont worry, sir. I dare say, nobody will come

21、again. 2) 作为行为动词作为行为动词dare在在 否定句中后面否定句中后面的可以省略的可以省略 He doesnt dare (to) go to the forest at night. The man never dares (to) do anything without his owners permission 5. dare “敢敢”，多用在否定或疑问句中。，多用在否定或疑问句中。 The little girl dare not speak in public. 小女孩不敢在公众小女孩不敢在公众面前说话。面前说话。 Dare you catch the little ca

22、t? 你敢抓小猫吗你敢抓小猫吗? dare 除用作情态动词外，更多的是当实义动词使用，除用作情态动词外，更多的是当实义动词使用， 用法同实义动词一样，要考虑人称，单复数，时态等。用法同实义动词一样，要考虑人称，单复数，时态等。 Do you dare to walk in the dark? 你敢黑夜走路吗？你敢黑夜走路吗？ He doesnt dare to tell the teacher what happened that day. 他不敢告诉老师那天发生的事。他不敢告诉老师那天发生的事。willI. 表现在经常发生的情况表现在经常发生的情况e.g., The man will go

23、to work every day.(= The man goes to work every day 后者更常用后者更常用)The door wont open. II.表示表示“决心决心”“”“意愿意愿”“”“可能可能”等等e.g If you will come tonight, hell meet you, I think. This will be the book you are looking for.Will you come in ? (=Will you please come in?)III. 若表示过去，则用若表示过去，则用woulde.g., He would tak

24、e a walk after supper when he lived in the country.He said he would help that girl.表示表示“过去常常过去常常”除了用除了用would，还可以用，还可以用used to，不过后者常常含有不过后者常常含有“现在不现在不”之意。之意。e.g., When young, he would go out for a trip on Sundays.(Now maybe still does)When young, he used to go out for a trip.(But now he doesnt)此外，此外，

25、would表示表示“过去常常过去常常”时后面动词须是某种时后面动词须是某种行为或动作，不能是静态动词行为或动作，不能是静态动词 。e.g., Near the village, there _ be a stream.A. would B. used toWould更多的用来表示语气而不是时态更多的用来表示语气而不是时态 Will/would you please do., Would you like to do., Would you mind doing. 都表示建议、询问、请求等。都表示建议、询问、请求等。e.g., Would/ Will you mind opening the w

26、indows?I would / will do anything for you , sir.有时甚至只能用有时甚至只能用would而不用而不用wille.g., I would like. Would you like.?They would love. He would rather shallI. 表示询问或征求别人的意见看法用于一、三人称表示询问或征求别人的意见看法用于一、三人称e.g., Shall I open the door?要我开门吗？要我开门吗？Shall he stay here for the night? 让他留下过夜吗？II.表示说话人的允诺，警告，命令，威胁等，

27、用于二、表示说话人的允诺，警告，命令，威胁等，用于二、三人称三人称e.g., If you work well ,you shall be well paid He says he wont come, but I say he shall. If you go there again, you shall lose what youve got.vIII表示规章，知识，预言等vEach competitor shall wear a number.vThe rules shall be obeyed.6反义疑问句反义疑问句在反意疑问句中，当附属部分含有表示推测意义的在反意疑问句中，当附属部分

28、含有表示推测意义的must, cant时，疑问部分的助动词应与时，疑问部分的助动词应与must ,cant后后面的动词在非推测情况下的用法保持一致。面的动词在非推测情况下的用法保持一致。 1. He must be a worker, ? 2. It must have rained last night, ? 3. You must have learned English for many years, ?4. He cant be a teacher, ? 5. She cant have finished her homework, ? didnt ithavent youisnt heis hehas she1. A computer _ think for itself; it must be told what to do. A. cant B. couldnt C. may not D. might not2. The fire spread through the hotel very quickly but everyone _ get out. A. had to B. would C. could D. was