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情态动词can/could
3. can/could 与be able to 相比 be able to 可用于各种时态，表能力，强调成功地做某事 was/were able to: 设法做成某事
相当于managed to do sth suceeded in doing sth
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情态动词may/might
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may/might表推测
1.may well”极有可能” e.g. Liza may well not want to go on the trip,because she dislikes travelling. 2.may/might as well”不妨” e.g. You may as well try to do it.
1.may表示请求别人允许 e.g. May I use your bike? 2.may/might表示可能性 e.g. He may be a teacher. 3. may用于表示,应该(多用于法律条文） e.g. Payment may be paid by check.
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情态动词shall/should
注：used to do “过去常常，强调现在不了”
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情态动词 must
1. must 表必须 e.g.You must keep the place clean. (务必) mustn't 禁止 e.g. When I was young, I was told that I mustn't play with fire. 2.must 还可表示“偏偏，偏要” e.g. Must you make so much noise?
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情态动词can/could
1. can表现在的能力 I can swim , but my sister can't.
2. could表过去的能力 At that time we thought the story could not be true.
3. You cannot smoke in the meeting room. (此句的cannot 表示 “禁止”)
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can? may? must? could? might ?
1. Jim ___can____ sing very well. 2. Hello, ___may/might___ I speak to Jim? 3. We are students. We _must__ work hard. 4. ____may/might_____ I come in? 5. You __can__ talk in class.. Nhomakorabea15
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can/could 表推测
1.常用于否定句和疑问句 e.g. He can't be at home. (否定句)
Can the news be true ? (疑问句) 2. can 用于肯定句中表示理论上的可能性，并不涉及是否真 的会发生 e.g.You can hurt yourself if you play in the street.
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情态动词 will/would
1. 用于向第二人称征求对方意见(would 比 will 更客气)
e.g. Would you please open the door?
2. will表示个人主观意愿
e.g. I will help you anytime.
3. would“表过去常常”
e.g. When he was there, he would go to that coffee shop every day.
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情态动词 must /have to
1. must 表示主观意愿，否定句用mustn’t，否定回答用 needn’t
e.g. You mustn’t play in the street.
－Must I clean the room now? －No,you needn’t. 2. have to表示客观条件的限制的“不得不”，它有时态和 人称变化，需要助动词来否定和疑问。
e.g. I don’t have to carry the big box.
He had to wash his clothes.
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情态动词表推测
可能性的强弱层次 must ＞should/ought to ＞can/could ＞ may/might 1. should/ought to表示推测 根据经验的推测，“应当、应该” e.g. Your photos should be ready by12:00. 表示“竟然”，带有感情色彩 e.g. It is incredible that you should like him.
1. 用于第一、三人称，征求对方意见 e.g. Shall we go now? What should we do next ? (用should 比 shall 表示更客气)
2.shall 用于法律、规定，表示义务和规定 8.g. The sign reads:No person shall smoke here! 3.should表示应该 e.g. You should not judge a man by his clothes.
情态动词
Modal Verbs
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情态动词是什么？
行为动词
动词类别
系动词 助动词
情态动词
能独立做谓语 不能独立做谓语
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情态动词是什么？
必须要和其他动词连用； 可表示说话人的语气，用来表达建议、要求、可能和意愿
等； 没有人称和数的变化。
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常用情态动词
现在式 can —— 过去式 could （能，可能） 现在式 may —— 过去式 might （可以） 现在式 shall —— 过去式 should （应该） 现在式 will —— 过去式 would （会，将要） must 无时态之分 had better、 dare、 need、 ought to