must_、have_to_区别及专项练习

must 与have to 的区别

情态动词must和have to都有“必须”的含义，它们的用法如下：

（一）、must “必须”、“应该”的用法:1.must 表示“必须”、“应该”。例如：

①We must protect our environment.(我们必须保护环境。）

②Everyone must obey the rule.（人人必须遵守制度。）

2. must的否定形式must not表示“不应该”、“禁止”、“不准”。语气比较强烈。例如：

①You mustn’t speak like that.(你不应该像那样讲话。）

②You mustn’t be late for school.（你不应该上学迟到。）

3.在回答must的问句时，肯定形式用must来回答，但否定形式用needn’t 或don’t have to来回答。而不用mustn’t来回答。例如：

①——Must I be home before 8 o’clock?(8点之前我必须回家吗？)

——Yes, you must. No, you needn’t./No, you don’t have to.

（是，你必须。）（不，你不必。）

（二）、have to 表示“必须”、“不得不”，例如：

①He has to stay in bed for 3 or 4 days.(他必须卧床休息三四天。）

②We will have to get up early tomorrow.（明天我们必须早起。）

补充：have got to是have to的口语形式。例如：

①I’ve got to leave for Nanjing.(我不得不去南京。)

*Must与have to的区别：

must表示的是说话人的主观看法，而have to则表示的是客观需要。Must一般只有现在时，而have to有更多的形式。

①I must go now.(主观看法)

②My mother is ill, so I have to go now.(客观需要)

*Have to与have got to的区别：

have got to虽然是have to的口语形式，但二者在用法上有严格的区别：have to的前面还可以用情态动词或助动词，而have got to却不可以；have to的否定形式为don’t/doesn’t /didn’t +have to,疑问式为Do/Does/Did + 主语+ have to…?而have got to的否定形式是在have后加not,疑问式把have提前。例如：

①We don’t have to go home.①Do you have to go home?

②We haven’t got to go home.②Have you got to go home?

专项练习1

1.----Must I do it now?

-----No, you _______.

A. needn’t

B. don’t have to

C. mustn’t

D. A or B

2.It’s nearly seven o’clock. Jack ______be here at any time.

A. must

B. need C should D can.

3.------When can I come for these photos? I need them tomorrow afternoon.

-------They ____be ready by 12:00.

A. can

B. should

C. might

D. need

4.They ___ do well in the exam.

A. can be able to

B. be able to

C. can able to

D. are able to

5, -Could I take this book out?

-No, you___.

A. can't

B. couldn’t

C. needn't

D. aren't

6. You___ go and see a doctor at once because you're got a fever.

A. can

B. must

C. dare

D. would

7.-Can you speak Japanese?

-No, I____.

A. mustn't

B. can't

C. needn't

D. may not

8. Even the top students in our class can't work out this problem, so it___ be very difficult.

A. may

B. must

C. can

D. need

9. He isn't at school. I think he ___ be ill.

A. can

B. shall

C. must

D. has to

10. The children___ play football on the road.

A. can't

B. can

C. mustn't

D. must

11.His arm is all right. He___ go and see the doctor.

A. has not to

B. don't have to

C. haven't to

D. doesn't have to

12. Excuse me. ___ you please pass me that cup?

A. Do

B. Should

C. Would

D. Must

13. -Would you like to go boating with us?

-Yes, ___.

A. I'd like

B. I want

C. I'd like to

D. I do