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Revision for
Modal Verbs
March,2004
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●The basic uses of Modal Verbs
6、 Dare
7、 Need
8、 ought to
9、三点说
明
10、典型错误
1、 Can / could
2、 May / might
3、 Must
4、 Shall / should
5、 will / would
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1. Can
1. 表示能力 The parrot can speak three languages.
2. 表示允许 Can I borrow the book from the library.
3. 表示可能性 Shanghai can be very cold in March.
Could 过去式；语气更委婉
2. Can 与 be able to
1. Can 表示习惯能力，
而 be able to表示经过那里而做成了某事。
2. 在否定结构中，二者可以互换。
3. can./could + have +p.p 1.在否定、疑问句中表示“对过去发生行为 的可能性猜测。
2. 在肯定句中表示“本来可以做而未做”
1. The door was lacked. She couldn’t have been at home.
2. You could have been more careful.
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1. May
1. 表示可能性
2. 表示允许
3. 表示祝愿 Might 过去式；语气更委婉
2. may/might + have +p.p 1.在否定、肯定句中表示对过去动作的推测 “ 也许是……”
2. Might+have+p.p表示虚拟，表“劝告、责备之意。”
Eg. 1. She may be still waiting for us.
2. May I come in?
3.May you have a happy holiday.
Eg.
1. He might have spoken to her yesterday.
2. You might have told me earlier.
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1. Must 1. 表示肯定的猜测 ,但只用于肯定句，
2. 而 mustn’t 表示“禁止、不准”
2. Must 、 have to
与 have got to
1. Must表示主观
2. Have to表示客观需求
3. Have got to 多见于口语
3. must + have +p.p 对过去事情的肯定猜测。
Eg.
The road id wet. It must have rained last night.
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1、 Shall /should
1、第一、三人称疑问句中表示“请求
或征求对方意见。
Eg. Shall I get you a cup of coffee?
2、第二、三人称陈述句中
1、表示允诺
“ 会（得到）。
2、表示命令 /警告
威胁 “该回必须”
2、 shall/should
+ have +p.p
ought to
表示本应该做而未做。
should 过去式
语气更委婉
Eg.
You should have been five minutes ago.
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Will/ would
1、表示意愿
I’ll try my best to overcome the difficulty.
2、表示意图
What will you do?
3、表示请示
Will you halp me to put these books in order?
4、表示习惯动作
She will sit for hours without saying a word.
Would 与 used to
1、 Would 后只能接表示动作的动词。
2、 used to 则还可以接表示状态的动词。
Eg.
He used to be a worker.
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1、情态动词用于否定、疑问句；条件从句中。
eg.
1. Dare you go here alone?
2. How dare you do such follish things?
3. I won’t allow you to swim in the river,
even if you dare do it.
Dare / dared
2 、做实意动词后加不定式。
eg.
I have never dared to tell him about it.
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Need /needed
1、情态动词用于否定句，疑问句。
2、实意动词用法似 dare,用作不定式。
3、 need + not + have +p.p
表示“本来不需要做而做了。
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Ought to
1、其否定式为 ought not to
2、 ought to + have + p.p
表示本来应该做而没有做到。
Eg.
You ought not to have cut away the trees around the old building.
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三点说明
1、情态动词 + v 表示对现在或将来动作的猜测。
情态动词 + have + p.p表示对过去动作的猜测。
2、情态动词的过去式与原形相比，多点礼貌，少点冒昧，
语气更为委婉。
情态动词在一般疑问句中的回答：
① Can you sing?
②May I come in?
③Must I handin the book now?
④ Need I finish it now?
Yes, I can.
No, I can’t.
Yes, you may.
No, you mustn’t.Yes, you must.
No, needn’t /don’t have to.
Yes, you must.
No, you needn’t.
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典型错误
1. He mustn’t be in the classroom. ( )Can’t
2. You might leave the bag on the bag. ( )might have left
3. You must have seen the film last week, have’t you?
( )didn’t you
4. Li ming must have been to Japan, didn’t he? ( )hasn’t he
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