The Subjunctive Mood(英语资料)(7)

肯定句中不用can, e.g. He could/may/might have gone swimming.

否定句中，cannot/couldn’t 不可能

e.g. She cannot/couldn’t have gone to school—it’s Sunday.

May/might not 可能不

They may not have considered me as their friend.

疑问句中，can/could, 不可用may/might e.g.

Can/could he have lost his way?

A: Who is playing the piano upstairs?

might

may

could

B: He can

should

ought to

would

will

must be Bob. (Compare: It is John.) 可能程度递增

Might, may, could: possibility

Should, ought to: expectation

Will, would: assumption

Must: certainty ; would, should也可表certainty.

Must 的三种否定形式：

He must be on the sports ground.

-->he can not be on the sports ground.

He must get up at five.

-->he needn’t get up at five.

He must park the car here.

-->he mustn’t park the car here.

he needn’t park the car here.

Ought to and should

Ought to表因责任，义务等客观上该做的事情，而should表主观上的看法，如:

You are his mother. You ought to take care of him.

You should tell the truth.

换句话说，ought to 有针对性，should 表一般的忠告。

We ought not to tell lies.我们可不应该说谎。

We should not tell lies. 我们不应该说谎话。

Used to

否定式：

He didn’t used to come.

He didn’t use to come.

He usedn’t to come.

疑问式：

Did he use to go to school with you?

Did you used to get up early?

Used he to get up early?