内容正文:
专题九 情态动词
情态动词: 本身有词义,但不能单独使用,没有人称和数的变化, 后跟动词原形 。
一.常见的情态动词及其用法:
词汇
含义及用法
例句
can
表示能力,意为“能、会”,可与be able to 互换
What sports can you play?
表示请求、允许,意为“可以”
Can we bring music players to school?
can’t
表示能力,意为“不会,不能”
They can’t leave school before they are 16 years old.
could
can 的过去式,意为“能,会”, 表示过去的能力
She could read by herself at the age of four.
在疑问句中表示委婉的请求
Could you just tell him to call me back?
couldn’t
意为“不会,不能”
I couldn’t believe it.
must
表示“必须”
I have an exam on Monday so I must prepare for it.
mustn’t
意为“不允许,禁止”
You mustn’t break anything.
may
表示请求、许可,意为“可以”,还可以表示祝福和愿望
You may sit here if you want.
might
may的过去式,表示请求、许可,语气比may更委婉
Might I read aloud here?
should
意为“应该”,表示要求和命令,也可以表示劝告或建议
I think you should lie down and rest.
shouldn’t
意为“不应该”
Kids shouldn’t play computer games until late at night.
need
表示必要性,主要用于否定句和疑问句中
needn’t
need的否定形式,表示“不必,无需”
-- So what do I do?
-- You needn’t wait!
would
will 的过去式,表示自愿做或主动提出做什么,如意志、愿望或决心等
Would you tell me the way to the airport?
have to
表示客观需要,意为“不得不”
I have to stay at home, for my sister is ill.
否定形式don’t have to,意为“不必”
You don’t have to come if you don’t want to.
shall
表示请求或征求对方意见,多用于第一,三人称,构成疑问句。
Shall I open the window?
表示决心,警告,命令,多用于陈述句的第二, 三人称中。
You shall not talk loudly at the cinema.
· have to与must的区别
· have to “不得不”,多表示客观原因。
Eg: You have to cut it up and eat it with a fork. 你不得不把它切碎然后用叉子吃。
· must 表示主观的必要性,意为“必须”。
---Must I finish my homework first?
---No, you don’t have to/needn’t.
二.情态动词表推测:
must
表示肯定推测,意为“一定,肯定”,表示非常有把握的肯定推测,100%的可能性
Most agree that the position of the stones must be for a special purpose.
can’t
表示否定推测,意为“一定不,不可能”,可能性几乎为零。
Miss Gao can’t be in the classroom. I just saw her in the supermarket.
could
表推测,意为“有可能,也许”
It could be Lily’s hair band. Or it might belong to Lucy. They both have long hair.
may
意为“ 有可能,也许 ”,用于肯定句,表示把握不大的推测
Jim may be sleeping now.
用于否定句,表示“可能不”
She may n