must 、have to 区别及专项练习

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)

② My 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