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5.must的主要用法
1. 必须。must表主观“必须”
have to 表客观“不得不”
I must go home this Saturday.
I’ve got a cold, so I have to see a doctor.
---Must I stay here? ---Yes, you must./ No, you needn’t./you don’t have to. ★mustn‘t 表禁止，不准，一定不要。 You mustn't play with fire. You mustn't take drugs.
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2. 表“偏要”“偏偏”，违背说话人意愿。 Must you talk in class? ---How much do you earn? ---I’ll tell you if you must know it. 3. 一定，肯定 He must be crazy. He must have stayed up last night. 4. 表推测的反应，反义疑问句中不能出现must的 形式，反义形式取决于句中时态
Unit 1
Modal Verbs
什么是情态动词？ (Modal Verbs) 情态动词表示说话人的某种 感情或语气，对某一动作 或状态的某种态度。 表示“需要、可以、can/could, 必须、应当”等。 may/might,
must/ have to, shall/should (ought to), will/would need, dare/dared
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• 情态动词的特点： 1.情态动词自身都有一定的意义， 但不能表示正在发生或已经发生的 事情，只表示期待或估计某事发生。 2.情态动词除ought和have外，后 面必须接不带to的不定式。 3.情态动词没有人称和数的变化, 也没有非谓语形式。
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(针对过去）
should/ought to have done
can’t/couldn’t have done could have done need have done needn’t have done
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1 Children under 12 years of age in that country ____ be under adult supervision when in a public library.
C. might
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D. should
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D 7. (10湖南23) You ______ buy a gift, but
you can if you want to.
A. must
C. have to
B. mustn’t
D. don’t have to
8. (10江西23) I have told you the truth. ______ A I keep repeating it? A. Must
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4.shall和should
shall 用法 1. shall表征求意见，用于一三人称
Shall we go by train, Mom? 疑问句中
Shall he attend the meeting?
2.用于二 三人称 的陈述句中，表威胁警告命令允诺等语
气
You shall get a present when I came back. You shall be punished if you break the rules.
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1.He must be my English teacher,
isn’t he?
2. He must have finished his homework, hasn’t he?
3. It must have rained yesterday,
didn’t it?
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should 用法
1. 应该=ought to
You should study hard.
2. 表万一，多位于句首。 Should he come, I would let you know. 3. “居然”，“竟然”,表说话人意料之外。 针对现在---- + V原 针对过去---- should have done To my surprise, he should be a thief. He should have lied to me yesterday.
(2004 上海）
A. must C. can
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B. may D. need
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2 Some aspects of a pilot’s job_____ be boring, and pilots often _____ work at inconvenient hours. （2006 湖南） A. can；have to
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2.may和might
may 常用来表示：
1. 在正式文体中表示请求、允许（比can正式）：:
eg. May I come in ? You may go now. 2. 表示说话人的猜测: “也许” “可能”: 通常只 用于肯定句和否定句中。
The guest may arrive this afternoon. ---Can he attend the meeting? ---Yes, he____. may I n’t have taken
D mustn’t have taken
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4 —How’s your tour around the North
Lake? Is it beautiful?
—It ________ be, but it is now heavily polluted. （2007 全国I）
A. will
C. should
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B. would
D. must
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5 I told your friend how to get to the
hotel, but perhaps I
have driven
her there. （2007 陕西） A. could B. must
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need & dare (dared) 情态动词 ： （无单三形式） need/dare do sth need/dare not do sth
实意动词：
need/dare to do sth
don’t/doesn’t/didn’t dare to do sth
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1.Being afraid of making mistakes ,he ____ answer his teacher's question A. doesn't dare C. daren't to B. doesn't dare to D. not dare to
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11. I can’t leave. She told me that I _____ B stay here until she comes back. (2009 全国卷II) A. can B. must C. will D. may 12. He must be helping the old man to water the flowers, _______? B (2009 陕西卷) A. is he B. isn’t he C. must he D. mustn’t he
1. can和could
1. can的主要用法是： A. 表能力 eg. The girl can dance very well. be able to 通过努力做成某事 He was able to reach Mount Qomolangma in 2000. B. 表示说话者的推测﹑事物的可能性:(否、疑） eg. Can the news be true? C. 在口语中, can可以表示请求或允许： eg. Can I sit here?
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B. Can
C. May
D. Will
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9. — It’s the office! So you _____ A know eating is not allowed here. — Oh, sorry. (2009湖南卷) A. must B. will C. may D. need 10. What do you mean, there are only ten tickets? There _______ A be twelve. (2009 全国卷I) A. should B. would C. will D. shall
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3. 表示祝愿,位于句首 eg. May you succeed! May you have a good journey! 4. may as well=had better do
(最好做某事）
You’d better take notes carefully. You may as well take notes carefully.
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3.will和would
will是助动词还是情态动词？ will用于构成将来时是助动词。 eg. I will tell you something important.