高一情态动词导学案.doc

高一情态动词导学案
情态动词记忆口诀:
情态动词两要点;动词原形跟后面,说话语气较委婉,can表"能力"may"许可",must"责任"或"义务",否定回答"needn't"换;should"应该",would"愿",have to "被迫"表客观.
注释:对must构成的一般疑问句作否定回答只能用needn't.
情态动词有can (could), may (might), must, have to, shall (should, will (would), dare (dared), need (needed), ought to等。情态动词无人称和数的变化;不能单独使用,必须与其后的动词原形构成谓语
一. can和could
情态动词
用法
例句
can/could
表示能力
1.“I don’t think Mike can type.”“Yes, he can.”
can speak fluent English now , but I couldn’t last year.
在肯定句中,表示客观可能性
a human being, anyone can make a mistake.
2. I’m confident that a solution can be found.
3. He can be very forgetful sometimes.
表示请求和允许。表示请求,口语中常用could代替can,使语气更委婉。
1. Can we turn the air conditioner on?
2. Could you have her call me back when she gets home, please?
3. I wonder if I could just ask you to sign this.
表示惊异、怀疑、不相信等态度,主要用在否定句、疑问句和感叹句中。
this be an excuse for not giving them help?
2. This can’t be true.
3. How can you be so crazy.
表示对现在的动作或状态进行主观的猜测,主要用在否定句和疑问句中。
1. It can’t be easy caring for a man and a child who are not your own.
2. Can the man over there be our head master?
特别说明:
(1) could用来表示请求时,语气委婉,主要用于疑问句,不能用于肯定句,答语应用can(即:could不能用于现在时态的简略答语中)。如:
——Could I use your dictionary?
——Yes, you can.(否定回答可用:No, I’m afraid not.)
(2) can和be able to辨析
can(could)和be able to都可以表示能力,意思上没有区别。但can只有现在式和过去式,而be able to则有更多的形式。如:
I’ve always wanted to able to speak fluent English.
Those bags look really heavy, are you sure you’ll be able to carry them on your own?
但是,表示在过去某时的某一场合经过一番努力,终于做成了某事,通常不用could,而用was/were able to来表示。这时,was/were able to相当于managed to eed in doing。如:
After the accident it was a long time before she was able to walk again.
The fire was very big, but most people were able to escape from the building.
惯用形式“cannot …too…”或“cannot/never…..enough 表示“无论怎么……也不(过分)”。如:
You can’t think too highly of him.
You cannot be too careful.= You can never be careful 。
I really cannot thank you ’s been an amazing day.
(4) 惯用形