Learning about Language课件配套优秀获奖教案

情态动词的基本用法

考点一：can 与could 的用法

1．

表示能力的can / could : (1) can 表示能力

/ 能时，只有现在时和过去时两种形式（can / could )

be able to 有更多的形式（am / is / are

able to ; was able to ; have / has been able to ; will be able to } (2) could 与was / were able to 在肯定句中不同。

could 表示过去一般的能力；表示过去的特定能力（即过去设法成功完成某一具体动作）时，用was / were able to do = managed to do =succeeded in doing . 在否定句中无区别。

eg; A blind man cannot judge colors.

The boy could speak three languages when he was 12.

The good swimmmer was able to swim to the river bank when the boat sank in the storm.(不用could)

Because he was tired ,he couldn’t / wasn’ t able to swim across the river . 2.表示许可的can / could

Can 可以代替may 表示“许可”，cannot表示“不可以”。could表示过去一般性许可（即表示某人随时都可以做某事）

eg: Can I use your mobile phone for a call ? Boys ,you cannot play football in the street . He asked me if he could take the book out of the library . When I lived at home ,I could watch TV whenever I wanted to . 3.表怀疑

/ 疑问，惊讶常用于疑问句中

（1）

can / c ould + 主语

+。。？表示怀疑，“能（是）。。。吗？

eg: Can the news true ? Can he have lied to us ?

(2) 特殊疑问词+can /could + 主语+。。？表示疑问，能（是）。。。呢？

eg: How could he be so careless? How could you do such a silly thing ? 4.表示推测的can /could

(1)can 用于肯定句中有时可用来表示推测，意为”有时会”；用于疑问句中可以表示推测，意为“

可能”，有时表示一种惊讶的语气；用于否定句中也可表示推测can’t 意为“不可能”语气很强烈。

eg : It is usually warm in my hometown in March ,but it can be rather cold sometimes .

Don’t

play with the dog ,Jack, for it can be dangerous at times.

Even experienced teachers can make mistakes.

There is no light in the room.She can’t be at home now .

(2)could 可以表示对将来事情的“可能性”的推测。

eg: You mustn’t smoke while you are walking around in the woods .You could start a fire.（不用can ）

5. can / could have done 表示“本来可以做，而实际上未做”或者“过去可能”；疑问或否定形式表示对过去发生的行为表示怀疑或不肯定，，其中“can’t / couldn’t have done 表”过去不可能做过。。“

eg:

We coud have faced the difficulty together ,but why didn’t you tell me ?

Sorry, Cathy , I didn’t know that you were badly short of money then. But you could have asked me for help .

Jenny took the 8:00 bus to Guangzhou this morning .Really? He could have taken the 9;00 train.It’s much more comfortable and safer to travel

by train. He can’t / couldn’ t have seen her there .

6．can 或could 的否定形式构成习惯用语：

cannot .....to 无论怎么样也不过分

cannot ......enough 无论如何也不过分

cannot (help)but do 不得不做只好做= have no choice but to do

cannot help doing 情不自禁做

cannot help it 没有办法

can’t ...+ (比较级)再。。。不过了（表示最高级意义）

eg : You cannot be too careful .=You cannot be careful enough .你越仔细越好/你怎么仔细也不过分

I can’t thank you enough .=I can’t thank you too much .我怎么感谢你也不过分/不胜感激/感激不尽

She couldn’t but agree to my idea .她只好同意我的想法。

The girl couldn’t help crying .这女孩忍不住哭了。

I burst out laughing ;I couldn’t help it .我突然大笑起来，无法克制自己。

The film couldn’t be any worse.那不电影再糟糕不过了。

考点二may 与might 的用法

1．

表示允许的may/might (指现在和将来)“可以”

（1）表示请求许可（请求别人允许自己做某事）might 比may 的语气委婉。

eg : May / Might I come into the room to see my mother ?

No ,you mustn’t / can’t .She needs a good rest . May / Might I take this magazine out ?

Yes , you may .(答语表示给予许可，不用might ) (2)表示给予许可（即自己允许别人做某事），通常用may 而不用might

eg : You may come in now.(不用might)

eg :He may be retire now .

I’m afraid it might rain tonight .

He may / might be writing a letter now .

She may /might have read it in a book .

I think you might have told us half an hour ago .

It may not be true .

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eg :

The doctor told me I must stop smoking .（指过去）

Cars must not be parked here . The children are sleeping .You mustn’t make any noise .

其否定形式为can’t （不可能）; must have done 表示对过去行为的推测“一定，想必”语气十分肯定。

eg :You haven’t eaten anything since morning ,you must be hungry .

He must be writing a letter to his girlfriengd now .

If the light were on ,they must have been at home. 3.eg :

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