重庆大学版（必修）英语2一年级《Theme A Learning to Be Relationship Between Parents and Children Unit 2 Parents and

重庆大学版（必修）英语2一年级《Theme A Learning to Be Relationship Between Parents and Children Unit 2 Parents and Children Grammar 》优秀教案设计

1) 情态动词没有人称和数的变化。(have to除外)

2) 有些情态动词有过去式, 有的过去式和它的原型相同。

a. 有过去式的有:

can — could may — might will — would

shall — should dare — dared need — needed

have to — had to

b. 过去式不变的有:

must — must ought to — ought to

情态动词的种类

要运用好情态动词，就要首先对情态动词有一个完整的认识，情态动词分为三种情况：

1.??只用作情态动词的有：

must, can / could, may / might, ought to, be able to

2.?既可作情态动词又可作实义动词的有：

need, dare，have /had to, used to

3.?既可作情态动词又为助动词的有：

shall / should / will / would

must:

1).表示必然性。

We must all die. 人总要死的。

. 表示强制/义务。

You must get up early. 你必须早起来。

. must not : “禁止”。

We mustn’t waste our time.

---- May I take this magazine out?

---- No, you mustn’t.