情态动词

must

1.表推测 ：肯定，一定 

You must be the new teacher.

It must have rained last night.

She must have cried just now.

2.表示不可避免的义务：必须

You must do it.(=have to)

may

1.表示推测：可能

The play may begin at any moment.

It may have began already.

2.表请求允许：可以吗？（第一人称）

May I do sth.

3.表示允许：可以

You may come in and have something to drink.

might

1.may 的过去式

2.用于现在时，是一种更加委婉的表述

may/might ...as well:    不妨...;不如...

This TV program is quite boring.We may/might listen to the music as well.

can

1.表示能力：能够

Trust yourself ! you can do it.

2.表示请求允许：可以吗？

3.表示允许：可以

4.表示推测（否定）：不可能

He is abroad, It can't be him.(couldn't)

could

1.can 的过去式

2.用于现在时，是一种更加委婉的表述

Could you help me?

8月27日暖言：不与任何人竞争，只要自己不断前进即可。

情态动词