1、情态动词用法比较表情态动词是一种本身有一定的词义，给谓语动词增添情态色彩，表示说话人对有关行为或事物的态度和看法，认为其可能、应该或必要等。情态动词后面加动词原形。分类情态动词有四类： 只做情态动词：must,can(could),may(might) 可做情态动词又可做实义动词：need,dare,will 具有情态动词特征：have(had,has) to,used to，ought to，had better情态动词表猜测：一肯一否三不定（must一肯，must not一否，can，could，would三不定。） 注：mustnt代表强烈禁止 must表示主观，have to表示客观
2、情态动词词义词义解释例句1may （might）能否、可否1) 表示请求和允许。might比 may语气更委婉，而不是过去式。否定回答时可用cant 或mustnt，表示“不可以，禁止”。 用May I.征徇对方许可时比较正式和客气，而用Can I.在口语中更常见。 2）用于祈使句，表示祝愿。 3) 表示推测、可能性（不用于疑问句）。 might不是过去式，它所表示的可能性比may小。 Can/ May I help you 我能帮助你吗May I have your name 我能知道你的名字吗He may be wrong , but Im not sure. 也许他错了，但我也不确定。-
3、Might/ May I smoke in this room - No, you mustnt. - May/Might I take this book out of the room - Yes, you can. (No, you cant / mustnt. ) He may /might be very busy now. Your mother may /might not know the truth. May you succeed! （祈使）2Will（would）决心,希望、愿望、愿意用于疑问句表示说话人向对方提出请求或询问, would 为 will 的过去式,用 wo
4、uld 比 will 更婉转,客气。1） (表示单纯的将来)将He will be home at six. 他六点回家。（将来时） 2） (表示意志、意愿)愿,要You will come, wont you 你会来的,是不是 3） (表示经常性、习惯性)经常,惯于,总是These things will happen. 这种事总是要发生的。 4） (表示猜测)可能,大概This will be the house youre looking for. 这大概就是你找的那所房子了。 5） (表示责任、义务)必须,一定No one will leave the examination room
5、 before ten oclock. 十点以前谁也不能离开考场。 3can (could)可以、能、同意表示说话人能,可以,同意,准许,以及客观条件许可,could 为 can 的过去式。 I can read this sentence in English. 我能用英语读这句话。 We can be there on time tomorrow.我们明天能按时去那儿。表推测：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。4Shall（should）应当、允许1) shall 用于第一人
6、称，征求对方的意见。 2) shall 用于第二、三人称，表示说话人给对方的命令、警告、允诺或威胁、劝告,建议惊奇。should, ought to表示“应该”，ought to表示义务或责任，比should语气重。 What shall we do this evening Shall we begin now我们现在就开始吗You shall fail if you dont work hard.(警告) He shall have the book when I finish it.(允诺)Its seven oclock. Jack should/ought to be here at
7、 any moment. 现在七点钟了，杰克理应随时到达。（推测）1. I should help her because she is in trouble. 2. You ought to take care of the baby.5Need需要,必须(多用于疑问句和否定句)需要,必须在肯定句中一般用must, have to, ought to, should代替。neednt + have + 过去分词 表示过去做了没必要做的事情（真不应.）1）情态动词：(多用于疑问句和否定句)需要,必须Need you go so soon 你需要这么早走吗 You neednt come so
8、early. - Need I finish the work today - Yes, you must. / No, you neednt. 2）实意动词：需要，有.必要The garden needs watering. 花园该浇水了。6ought to应当,应该1) should, ought to表示“应该”，ought to表示义务或责任，比should语气重。 2) 表示劝告、建议和命令。should, ought to可通用，但在疑问句中常用should。 3) 表示推测 should , ought to (客观推测), must(主观推测)。 ought to have d
9、one 句型。指过去动作,表示一件事情该做而未做。 ought not to have done 句型。表示一件不该做的事情却做了。Tom should not /ought not to have told me your secret,but he meant no harm. （虚拟） 汤姆本不该告诉我你的秘密，可是他并无恶意。You ought to have been here yesterday. 你昨天就应该来。 You ought not to have taken the book out of the reading-room. 你不应该把书带出阅览室。I should h
10、elp her because she is in trouble. You ought to take care of the baby.You should / ought to go to class right away. Should I open the windowHe must be home by now. (断定他已到家) He ought to/should be home by now.(不太肯定) This is where the oil must be.(直爽) This is where the oil ought to/should be.(含蓄)7must必
11、须,应该,一定,准是,偏要否定式 mustnt 意为“一定不要”“不允许”表示说话人认为有必要做某事, 命令, 要求别人做某事以及对事物的推测。1) 表示“必须”此时可用于肯定句、否定句或疑问句，用于否定句时，mustnt的意思是“一定不要”“不能”，而不表示“不必”。2) 表示推测意为“准是”“一定是”，通常只用于肯定句。若用于否定句或疑问句，则用 can 代之3) 表示“偏偏”对于must开头的一般疑问句，若作否定回答，可以用neednt，不用 mustnt。如：“Must I clean all the rooms” “No, you neednt.”1）(表示必要、命令或强制)必须,得
12、You mustnt talk like that. 你可不能这样说话。 We must be home by six. 我们必须在六点以前回家。You must obey the school rules.你必须遵守校规。2）(表示肯定的推测)一定是,谅必,八成This must be your room. 这一定是你的房间了He must be eighty now. 他现在八成有八十岁了。3) 表示“偏偏”有时must可表示某事发生得不早不迟，就在某个当紧的时候，多指某些不受欢迎的事情的发生。如：The car must break down just we were starting
13、our holidays. 我们刚刚开始休假，汽车偏偏坏了。Just when I was busy, the neighbor must come and chatter. 正当我忙碌的时候，邻居偏偏过来聊天。9have to不得不,必须have to的否定式dont have to 意为“不必”(=neednt)表示客观条件只能如此, 而must 则表示主观思想必须。have to有时态三单数。如否定句用 doesnt/dont/didnt+have to + 动词原形must, have to的区别1) 表示必须、必要。 2) must是说话人的主观看法， 而have to则强调客观需要
14、。Must只有一般现在时（在从句中可有过去时），have to 有更多的时态形式。 3) 表示推测、可能性（只用于肯定的陈述句） I know I must study hard.我知道我必须努力学习。My brother was very ill, so I had to call the doctor in the mid-night.我弟弟病得厉害， 我只得半夜里把医生请来。I havent got any money with me, so Ill have to borrow some from my friend.我身上没带钱，只好向朋友借点了。与must的区分：You must
15、come in time. 在回答引出的问句时，如果是否定的，不能用mustnt（禁止，不准），而用neednt, dont have to（不必）. - Must we hand in our exercise books today - Yes, you must. - No, you dont have to / you neednt. he play isnt interesting, I really must go now. I had to work when I was your age. Youre Toms good friend, so you must know wha
16、t he likes best. Your mother must be waiting for you now. 8had better同had best最好。had better not最好别1）He had better stay in bed tomorrow. 他最好明天卧床休息。2）You had better not say it again. 你最好不要再提那件事了。10would rather宁愿、宁可意为“宁愿”，表选择。1）Would you rather work on a farm 2） Wouldnt you rather stay here No,I would
17、not. Id rather go there.11used to过去常常usednt to 过去不常used to do 表示过去常常做某事，而现在往往不做了used to 与would的用法比较(1) 两者都表示过去的习惯，当表示过去习惯性的动作时，可互换。如：When we were children we would used to go skating every winter. 我们小时候，每年冬天都去溜冰。(2) 若表示过去持续的状态，通常只用used to，不用would。如：He used to like you. 他原来还是喜欢你的。(3) 若要强调过去与现在的对比，也通常
18、只用used to。如：I dont smoke these days, but I used to. 我现在不抽烟，但我以前是抽的。I used to drive to work but now I cycle. 过去我常驾车上班，但我现在骑自行车。I used to write poetry when I was young我年轻时常常写诗。Do you play golf No, but I used to. “你打高尔夫球吗”“不打，但我过去打。You used to go there, usednt didnt you 你过去常到那儿去，是吗Where did you use to
19、live 你过去是住哪儿的He usednt didnt use to come. 他过去不常来。12dare敢;竟敢dare作情态动词用时, 常用于疑问句、否定句和条件从句中, *过去式形式为dared。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。情态动词1）敢;竟敢How dare you ask me such a question 你怎敢问我这样的问题 My younger sister dare not go out alone. 我妹妹不敢单独出去。If we dared not go there that day， we could
20、nt get the beautiful flowers.如果那天我们没敢去那儿，那么我们不能得到鲜花。及物动词2）敢;胆敢He did not dare to leave his car there. 他不敢把车停放在那里。【模拟试题】（答题时间：30分钟）单项选择： 1. John_ come to see us tonight, but he isnt very sure yet.A. may B. can C. has to D. must 2. They _ do well in the exam.A. can be able to B. be able to C. can able
21、 to D. are able to 3. May I take this book outNo, you_.A. cant B. may not C. neednt D. arent 4. You_ go and see a doctor at once because youre got a fever.A. can B. must C. dare D. would 5. Can you speak JapaneseNo, I_.A. mustnt B. cant C. neednt D. may not 6. He_ be in the classroom, I think. No, h
22、e _ be in the classroom. I saw him go home a minute ago. A. can; may not B. must; may not C. may; cant D. may; mustnt 7. Shall I get one more cake for you, DadThanks, but you_, Ive had enough.A. may not B. must not C. cant D. neednt 8. Even the top students in our class cant work out this problem, s
23、o it _be very difficult.A. may B. must C. can D. need 9. He isnt at school. I think he _ be ill.A. can B. shall C. must D. has to 10. _ I take this oneA. May B. Will C. Are D. Do 11. The children_ play football on the road.A. cant B. can C. mustnt D. must 12. You _ be late for school again next time
24、.A. mustnt B. neednt C. dont have to D. dont need to 13. Must I do my homework at onceNo, you_. A. neednt B. mustnt C. cant D. may not 14. His arm is all right. He_ go and see the doctor.A. has not to B. dont have to C. havent to D. doesnt have to 15. He had to give up the plan, _ heA. did B. didnt
25、C. does D. doesnt 16. They had to walk here, _ theyA. mustnt B. did C. didnt D. hadnt 17. He had better stay here, _ heA. didnt B. dont C. hadnt D. isnt 18. Youd better_ late next time.A. not to be B. not be C. wont be D. dont be 19. Youd better _ your hair _ once a month.A. had; cut B. had; cutted
26、C. have; cut D. have; cutted 20. You_ ask that man over there. Maybe he knows the way. A. had better not to B. had not better C. had better D. had better not 21. Shall we go and visit the History Museum next Sunday _A. Here you are B. Sorry, I cant C. Yes, please D. Let me try 22. Why dont you ask M
27、ike to go with usThanks, _.A. I will B. I wont C. I can D. I may 23. _ I take the newspaper awayNo, you mustnt. You_ read it only here.A. Must; can B. May; can C. Need; must D. Must; must 24. Excuse me. _ you please pass me that cupA. Do B. Should C. Would D. Must 25. _ you like to have another tryA
28、. Could B. Will C. Would D. Do 26. Would you like to go boating with usYes, _.A. Id like B. I want C. Id like to D. I do 27. You_ worry about your son. He will get well soon. A. neednt B. cant C. mustnt D. have to 28. The poor man needs our help, _ heA. need B. neednt C. does D. doesnt 29. Must we do our homework firstNo, you_. You may have a rest first.A. mustnt B. neednt C. may not D. cant【试题答案】15 A D A B B 610 C D B C A 1113 C A A 1416 D B C1720 C B C C 2123 B A B 2426 C C C 2729 A D B
