Modal Verbs

情態動詞

情態動詞表示說話的語氣或情態。情態動詞本身有詞義，但不完全， 不能單獨作謂語， 必須和動詞一起構成謂語。

情態動詞沒有人稱和數的變化。

大多數情態動詞有過去式。

主要情態動詞：

can, may, will ,must ,shall ,need, dare, had, better, would, sooner, would, as soon, could, might, would, have to, should, ought to, used to, would rather, might, as well

情態動詞問題解析:

1. may be & maybe

May be （可能是）—maybe （或許）（副詞）

The news may be true.

Maybe the news is true.

She may be waiting for you at home.

Maybe she is waiting for you at home.

2. May not & can not

may not 譯為“可能不”、“也許不會”而非“不可以”。“不可以”為must not或can't（不許，不可以）。

---May I smoke here?

---No, you mustn't. /you can't /you can not.

The news may not be true.

You mustn't move any of the papers on the desk.

3. Can & be able to

Be able to 可以表示更多的時態。

We will be able to finish the work tomorrow.

He was not able to realize his greatest ambition.

Are you able to design a new computer program?

She has not been able to work out the complex problem.

4. ought to的否定式

ought to的否定式是ought not to，疑問句只把ought提前。

You ought to be responsible for yourself.

We ought not to look down on disabled people.

Ought we to count on him for the settlement of the debate?

5. Must

Must do

Must be

Must have done

6. Must 的反意疑問句

I must get up at six, ___?

She must be in the classroom now, _____?

They must have had great trouble trying to get there, ____?

7. 用must 提問時的回答

肯定回答：must

否定回答：needn't或don't /doesn't have to

Must I come as early as 6 tomorrow morning?

Yes, you must.

No, you needn't. / No, you don't have to.

8. Mustn't & Needn't

Must he arrive very early?

No, he doesn't have to / No, he needn't.

9. Must & have to

Must: 主觀上認為“必須” 作某事。

Have to: 受客觀情況迫使而“不得不” 作某事

You must work harder now if you want to find a satisfactory job after graduation.

Children in remote areas have to quit school simply because their parents cannot afford their education.

I must help him. {obligation, responsibility}

I have to help him. {unwillingness)

10. Must & have to的否定

否定must 表示“禁止，不允許，一定不要”

否定don't have to 表示“不必,不一定非得,不一定要”

We mustn't put off the trip no matter what happens.

We don't have to put off the trip, although it rains.

11. Must & have to時態的區別

Must只用于現在, 而have to則可用于不同時態。用had to表示過去 , 用will have to表示將來。

We had to resort to force in that case.

We will have to reconsider the whole thing if this plan fails.

One must have faith in life.

12. have to

have to的疑問句和否定句都要用助動詞do/does，過去式則用did。

Do we have to wait for him to start dinner?

Does he have to show you the tickets to enter the cinema?

Did I have to do the other task as well?

You don't have to come in person.

She doesn't have to bring her dictionary.

We didn't have to make preparations for the quiz.