论文部分内容阅读
have to, must, ought to,should, need,
在英语中有一组表示责任､义务､需要或强制命令的情态动词,如have to, must, ought to, should, need, had better等,学生较难明白区分,下面试作一总结｡
一､ have to 与must的用法
1) 有时可通用｡例如:
You must (have to) do as you are told.要你怎么做你就得怎么做｡
2) 表示个人意志或主观上的必要性时常用must,表示客观上的必要性时常用have to｡试比较:
We must study hard. 我们一定要努力学习｡
I have no bike. I have to go to the office on foot. 我没有自行车,上班只得步行｡
3) 表示经常性的动作时宜用have to｡例如:
I have to take care of my mother every day. 我得每天照顾我母亲｡
4) must只有一种形式,在将来时里既可用must, 也可用shall (will) have to｡例如:
I must be at home tomorrow. 我明天一定在家｡
I shall have to go there some day. 我总有一天要到那里去｡
5) must 一般不用过去时,它的过去时常用had to 代替｡例如:
I had to finish it yesterday. 我昨天不得不要完成那件了｡
6) must意为“必须”时,否定式是needn’t, mustn’t表示“绝对不可,不许,禁止”,have to 的否定式表示“不必”｡例如:
You musn’t smoke in class. 上课时不准吸烟｡
You don’t have to recite the text before class. 你不必在上课前背书｡
You must pay the money, but you needn’t do so at once. 你必须付钱,但不必马上付｡
—Must I finish my homework now? 我必须现在就完成作业吗?
—Yes, you must. 是的｡
—No, you needn’t. / Don’t have to. 不,你不必｡
7) 注意must 在表达“必须､一定”的含义时,反意疑问句用mustn’t｡表示“有必要”之意时,反意疑问句则要用needn’t｡表示“禁止”的意思时,反意疑问句常用may,也可用must｡例如:
You must finish your homework on time, mustn’t you?
They must buy a dictionary now, needn’t they?
You mustn’t play football in the classroom, may( must) you?
二､ ought to的用法
1) 英语中的ought to为情态动词,意思是“应该;应当”,可用于各种人称的句中,没有词形变化｡后接动词原形时可以表示现在､将来或过去将来的时间概念,由时间状语或上下文决定｡例如:
He thought that they ought to take part in the design. 他认为他们应当参加设计｡
2) ought to表示义务､约束力,意为“应该,应当”,语气比should强,比must弱｡如:
You ought to follow him. 你应该听他的话｡
There ought not to be much noise in a hospital. 医院里不该喧闹｡
3) ought to 的否定式是ought not to或oughtn’t to, 疑问句是把ought提到主语前面｡例如:
She ought not to buy this book. 她不应该买这本书｡
He oughtn’t to go there. 他不该去那儿｡
注意: 其否定式不使用ought to not的形式｡
Ought I to leave tomorrow? 我应当明天动身吗?
4) 在反意疑问句中,下面两种形式都可以:
David ought to stay at home to look after his mother, shouldn’t he? / oughtn’t he? 大卫应当呆在家里照顾他母亲,是吗?
5) 后接不定式完成式的用法如下:
ought / oughtn’t to have done意为“本应该做某事(但实际上没有做);本不应该做某事(但做了)”,表示事与愿违,往往含有批评或责备的意思｡例如:
We ought to have given you more help. 我们本应该给你更多帮助｡(表示自责或遗憾)
You oughtn’t to have done that. 你本不该那样干｡(表示批评)
6) 后接不定式完成进行式,意为“应该一直在做某事”,表示责备､批评､推测等｡例如:
You ought to have been waiting for us. Why haven’t you? 你本应当等着他们,怎么没等?(表示责备)
You oughtn’t to have been talking so much. 你本不应该讲这么多话｡(表示批评)
7) 其被动式为ought to be done｡例如:
Teachers ought to be honored. 老师应该受到尊敬｡
Such things ought not to be allowed, ought they? 这类事情不应该准许,是吗?
三､ should的用法
1) 用于提出建议或劝告,意思是“应当､应该”｡例如:
He should be criticized since he is often late for class. 既然他经常上课迟到,他应该受到老师批评｡
One shouldn’t judge a person by his appearance. 不应该以貌取人｡
2) 用在二､三人称中具有“强制､威胁”之意｡例如:
You should do it as I told you. 你要按照我告诉你的去做｡(强制)
They should return all these balls as soon as the P.E. class is over. 体育课一结束他们就得把所有的球还上｡(命令)
3) should have done表示“本应该做而实际上未做”;shouldn’t have done表示“本不应该做而做了”｡例如:
He also learns that he should have cared more about his friends. 他还明白了他本来应该多关心朋友｡
You shouldn’t have quarreled with her last night. 昨晚你本来不应该和她争吵的｡
四､ need的用法
1) 作情态动词用的need只用于否定句和疑问句,意为“需要;必须”｡例如:
—You needn’t try it again. 你不必再试｡
—Need they stay here this evening? 他们今晚要住在这儿吗?
—Yes, they must (have to). 是的,他们要住在这儿｡
—No, they needn’t. 不,他们不必住在这儿｡
2) need还可以用作实义动词｡例如:
He needs some money. 他需要点钱｡
You don’t need to wait. 你不必再等了｡
—Does he need to return? 他需不需要回来?
—Yes, he does. (No, he doesn’t). 需要｡(不需要｡)
3)need 可用于指现在时及将来时,need没有另外的过去时形式,在过去时中常用had to｡例如:
He had not to go yesterday. 他昨天可不必去｡
4) needn’t have +过去分词表示“本不必做某事而做了”｡例如:
Your elder brother needn’t have come last night. 你哥哥昨晚本不必来｡
五､ had better的用法
had better意为“最好”,有时也可用had best的形式,常用于表示比较委婉的建议,其后习惯加动词原形,其否定形式为had better not do sth.｡例如:
It’s a long way for us to cover. We’d better / best take a bus. 路太远了,我们最好乘公共汽车去｡
You’d better not say such silly words. 你最好不要说这种愚蠢的话｡
【即时巩固练习】
1. —Shall I tell John about it?
—No, you________. I’ve told him already.
A. needn’t
B. wouldn’t
C. mustn’t
D. shouldn’t
2. When he was there he________ go to that coffee shop at the corner after work every day.
A. had to
B. should
C. had better
D. might
3. —Can I tell my best friend about it?
—No, I don’t want anyone else to know it.
You________ keep it yourself.
A. can
B. need
C. must
D. may
4. It was playing computer games that cost the boy plenty of time that he________ have spent doing his lessons.
A. might
B. must
C. ought to
D. could
5. One ought________ for what one hasn’t done.
A. not to be punished
B. to not be punished
C. not punished
D. not be punished
6. —________he clean the classroom now?
—No, he________. He may do it tomorrow.
A. Must; mustn’t
B. Need; wouldn’t
C. Shall; needn’t
D. May; don’t have to
7. This project________ considered thoroughly (彻底地), and I’m sure it________ finished on time.
A. must be; may be
B. should be; can be
C. may be; must be
D. can be; should be
8. We________ last night, but we went to the concert instead.
A. must have studied
B. might study
C. should have studied
D. would study
9. —________shopping himself yesterday afternoon?
—No, he needn’t have.
A. Could he have gone
B. Must he go
C. Need he have gone
D. Did he go
10. I don’t think it advisable that Jack________ the job since he has little experience.
A. is given
B. will be given
C. be given
D. has been given
11. —May I go out to play football for a______ while?
—No, you________.
A. needn’t
B. mustn’t
C. won’t
D. may not
12. —I’m sorry, Mrs Smith. I’ve broken your______ glasses.
—It doesn’t matter, Mark, but you_______careful.
A. must be
B. should be
C. must have been
D. should have been
13. —She didn’t pass the exam yesterday.
—She________ it well.
A. must have prepared
B. should have prepared
C. must have prepared for
D. should have prepared for
14. —Everybody is supposed to start the work________ at 8:30.
—Well, I know I________ this morning, but________ my car broke down.
A. ought to
B. ought to have
C. should
D. must have
15. —Did your father go to America?
—No, his doctor suggested that he________there.
A. is going
B. not go
C. did not go
D. to be doing
16. It was, I should say, very kind of you to come all the way to help them, but you_______ .
A. didn’t have to
B. wouldn’t have done
C. mustn’t have done
D. mightn’t have done
17. —Mr Simth didn’t come last night, did______ he?
—No, we________ have waited for him. A______whole night was wasted.
A. couldn’t
B. needn’t
C. should
D. would
18. We are really shocked at their decision that the engineer________ be given the sack(开除).
A. must
B. should
C. may
D. can
19. —I don’t mind telling you what I know.
—But you________. I’ve known all about it.
A. mustn’t
B. may not
C. can’t
D. needn’t
20. —I sent him the dictionary by mail this______ afternoon.
—You________ that; he’s coming next week.
A. mustn’t do
B. didn’t have to do
C. needn’t have done
D. needn’t to do
Keys: 1. A2. A3. C4. C5. A6. C7. B8. C9. C10. C11. B12. D13. D14. B15. B16. A17. B18. B19. D20. C
在英语中有一组表示责任､义务､需要或强制命令的情态动词,如have to, must, ought to, should, need, had better等,学生较难明白区分,下面试作一总结｡
一､ have to 与must的用法
1) 有时可通用｡例如:
You must (have to) do as you are told.要你怎么做你就得怎么做｡
2) 表示个人意志或主观上的必要性时常用must,表示客观上的必要性时常用have to｡试比较:
We must study hard. 我们一定要努力学习｡
I have no bike. I have to go to the office on foot. 我没有自行车,上班只得步行｡
3) 表示经常性的动作时宜用have to｡例如:
I have to take care of my mother every day. 我得每天照顾我母亲｡
4) must只有一种形式,在将来时里既可用must, 也可用shall (will) have to｡例如:
I must be at home tomorrow. 我明天一定在家｡
I shall have to go there some day. 我总有一天要到那里去｡
5) must 一般不用过去时,它的过去时常用had to 代替｡例如:
I had to finish it yesterday. 我昨天不得不要完成那件了｡
6) must意为“必须”时,否定式是needn’t, mustn’t表示“绝对不可,不许,禁止”,have to 的否定式表示“不必”｡例如:
You musn’t smoke in class. 上课时不准吸烟｡
You don’t have to recite the text before class. 你不必在上课前背书｡
You must pay the money, but you needn’t do so at once. 你必须付钱,但不必马上付｡
—Must I finish my homework now? 我必须现在就完成作业吗?
—Yes, you must. 是的｡
—No, you needn’t. / Don’t have to. 不,你不必｡
7) 注意must 在表达“必须､一定”的含义时,反意疑问句用mustn’t｡表示“有必要”之意时,反意疑问句则要用needn’t｡表示“禁止”的意思时,反意疑问句常用may,也可用must｡例如:
You must finish your homework on time, mustn’t you?
They must buy a dictionary now, needn’t they?
You mustn’t play football in the classroom, may( must) you?
二､ ought to的用法
1) 英语中的ought to为情态动词,意思是“应该;应当”,可用于各种人称的句中,没有词形变化｡后接动词原形时可以表示现在､将来或过去将来的时间概念,由时间状语或上下文决定｡例如:
He thought that they ought to take part in the design. 他认为他们应当参加设计｡
2) ought to表示义务､约束力,意为“应该,应当”,语气比should强,比must弱｡如:
You ought to follow him. 你应该听他的话｡
There ought not to be much noise in a hospital. 医院里不该喧闹｡
3) ought to 的否定式是ought not to或oughtn’t to, 疑问句是把ought提到主语前面｡例如:
She ought not to buy this book. 她不应该买这本书｡
He oughtn’t to go there. 他不该去那儿｡
注意: 其否定式不使用ought to not的形式｡
Ought I to leave tomorrow? 我应当明天动身吗?
4) 在反意疑问句中,下面两种形式都可以:
David ought to stay at home to look after his mother, shouldn’t he? / oughtn’t he? 大卫应当呆在家里照顾他母亲,是吗?
5) 后接不定式完成式的用法如下:
ought / oughtn’t to have done意为“本应该做某事(但实际上没有做);本不应该做某事(但做了)”,表示事与愿违,往往含有批评或责备的意思｡例如:
We ought to have given you more help. 我们本应该给你更多帮助｡(表示自责或遗憾)
You oughtn’t to have done that. 你本不该那样干｡(表示批评)
6) 后接不定式完成进行式,意为“应该一直在做某事”,表示责备､批评､推测等｡例如:
You ought to have been waiting for us. Why haven’t you? 你本应当等着他们,怎么没等?(表示责备)
You oughtn’t to have been talking so much. 你本不应该讲这么多话｡(表示批评)
7) 其被动式为ought to be done｡例如:
Teachers ought to be honored. 老师应该受到尊敬｡
Such things ought not to be allowed, ought they? 这类事情不应该准许,是吗?
三､ should的用法
1) 用于提出建议或劝告,意思是“应当､应该”｡例如:
He should be criticized since he is often late for class. 既然他经常上课迟到,他应该受到老师批评｡
One shouldn’t judge a person by his appearance. 不应该以貌取人｡
2) 用在二､三人称中具有“强制､威胁”之意｡例如:
You should do it as I told you. 你要按照我告诉你的去做｡(强制)
They should return all these balls as soon as the P.E. class is over. 体育课一结束他们就得把所有的球还上｡(命令)
3) should have done表示“本应该做而实际上未做”;shouldn’t have done表示“本不应该做而做了”｡例如:
He also learns that he should have cared more about his friends. 他还明白了他本来应该多关心朋友｡
You shouldn’t have quarreled with her last night. 昨晚你本来不应该和她争吵的｡
四､ need的用法
1) 作情态动词用的need只用于否定句和疑问句,意为“需要;必须”｡例如:
—You needn’t try it again. 你不必再试｡
—Need they stay here this evening? 他们今晚要住在这儿吗?
—Yes, they must (have to). 是的,他们要住在这儿｡
—No, they needn’t. 不,他们不必住在这儿｡
2) need还可以用作实义动词｡例如:
He needs some money. 他需要点钱｡
You don’t need to wait. 你不必再等了｡
—Does he need to return? 他需不需要回来?
—Yes, he does. (No, he doesn’t). 需要｡(不需要｡)
3)need 可用于指现在时及将来时,need没有另外的过去时形式,在过去时中常用had to｡例如:
He had not to go yesterday. 他昨天可不必去｡
4) needn’t have +过去分词表示“本不必做某事而做了”｡例如:
Your elder brother needn’t have come last night. 你哥哥昨晚本不必来｡
五､ had better的用法
had better意为“最好”,有时也可用had best的形式,常用于表示比较委婉的建议,其后习惯加动词原形,其否定形式为had better not do sth.｡例如:
It’s a long way for us to cover. We’d better / best take a bus. 路太远了,我们最好乘公共汽车去｡
You’d better not say such silly words. 你最好不要说这种愚蠢的话｡
【即时巩固练习】
1. —Shall I tell John about it?
—No, you________. I’ve told him already.
A. needn’t
B. wouldn’t
C. mustn’t
D. shouldn’t
2. When he was there he________ go to that coffee shop at the corner after work every day.
A. had to
B. should
C. had better
D. might
3. —Can I tell my best friend about it?
—No, I don’t want anyone else to know it.
You________ keep it yourself.
A. can
B. need
C. must
D. may
4. It was playing computer games that cost the boy plenty of time that he________ have spent doing his lessons.
A. might
B. must
C. ought to
D. could
5. One ought________ for what one hasn’t done.
A. not to be punished
B. to not be punished
C. not punished
D. not be punished
6. —________he clean the classroom now?
—No, he________. He may do it tomorrow.
A. Must; mustn’t
B. Need; wouldn’t
C. Shall; needn’t
D. May; don’t have to
7. This project________ considered thoroughly (彻底地), and I’m sure it________ finished on time.
A. must be; may be
B. should be; can be
C. may be; must be
D. can be; should be
8. We________ last night, but we went to the concert instead.
A. must have studied
B. might study
C. should have studied
D. would study
9. —________shopping himself yesterday afternoon?
—No, he needn’t have.
A. Could he have gone
B. Must he go
C. Need he have gone
D. Did he go
10. I don’t think it advisable that Jack________ the job since he has little experience.
A. is given
B. will be given
C. be given
D. has been given
11. —May I go out to play football for a______ while?
—No, you________.
A. needn’t
B. mustn’t
C. won’t
D. may not
12. —I’m sorry, Mrs Smith. I’ve broken your______ glasses.
—It doesn’t matter, Mark, but you_______careful.
A. must be
B. should be
C. must have been
D. should have been
13. —She didn’t pass the exam yesterday.
—She________ it well.
A. must have prepared
B. should have prepared
C. must have prepared for
D. should have prepared for
14. —Everybody is supposed to start the work________ at 8:30.
—Well, I know I________ this morning, but________ my car broke down.
A. ought to
B. ought to have
C. should
D. must have
15. —Did your father go to America?
—No, his doctor suggested that he________there.
A. is going
B. not go
C. did not go
D. to be doing
16. It was, I should say, very kind of you to come all the way to help them, but you_______ .
A. didn’t have to
B. wouldn’t have done
C. mustn’t have done
D. mightn’t have done
17. —Mr Simth didn’t come last night, did______ he?
—No, we________ have waited for him. A______whole night was wasted.
A. couldn’t
B. needn’t
C. should
D. would
18. We are really shocked at their decision that the engineer________ be given the sack(开除).
A. must
B. should
C. may
D. can
19. —I don’t mind telling you what I know.
—But you________. I’ve known all about it.
A. mustn’t
B. may not
C. can’t
D. needn’t
20. —I sent him the dictionary by mail this______ afternoon.
—You________ that; he’s coming next week.
A. mustn’t do
B. didn’t have to do
C. needn’t have done
D. needn’t to do
Keys: 1. A2. A3. C4. C5. A6. C7. B8. C9. C10. C11. B12. D13. D14. B15. B16. A17. B18. B19. D20. C