Grammar

1. Grammar Grammar 情态动词用法

2. 情态动词的语法特征 • 情态动词有一定的意义，表示或暗示某种情绪或 • 态度，表示可能、建议、愿望、必要、允许、能力等。 • 2. 情态动词没有人称和数的变化，即不随主语的不同而变化。 • 3. 情态动词不能独立使用，必须和实义动词一起构成谓语。 • 4. 情态动词除ought和have外，后面只能接不带to的不定式。 • 5. 情态动词没有非谓语形式，即没有不定式、分词等形式。

3. 只作情态动词的 can / could, may / might, ought to, must 可情态可实义的　 need, dare 可情态可助动词的 shall / should, will / would 相当于情态动词的 have to, used to

4. must和 have to 1.must用于一般问句中,肯定回答用must否定式用 needn’t或don’t have to，做 “不必”, mustn’t表示“禁止，不允许”  — Must I finish all assignments at a time?   —Yes, you must. No, you needn't.

5. 2.表示“必须”这个意思时，must 和have to 稍有区别。must着重说明主观看法，have to 强调客观需要。另外，have to 能用于更多时态。2.表示“必须”这个意思时，must 和have to 稍有区别。must着重说明主观看法，have to 强调客观需要。另外，have to 能用于更多时态。 I don’t like this TV set. We must buy a new one. There was no more bus. They had to walk home.

6. 3.must表示对某人某事的猜测, 作“准是”, “一定” , 一般用于肯定句中。对过去发生的事情作肯定判断用must have done  Youmust be the new teacher.   He must be joking. There is nobody here. They must have all gone home.

7. 4. must表示“偏要, 硬要”, 指做令人不快的事情 He must come and worry her with question, just when she was busy cooking the dinner. Of course，after I gave her my advice，she must go and do the opposite.

8. can (1)表示能力 Can you speak Japanese? (2)表示推测时，只用在否定句或疑问句中。 He can’t be at home now. (3) 表示允许 Can I have a look? (4) 表惊异、怀疑等 How can you be so rude? could可表示能力或可能性，多用于过去，也可指现在，通常表示虚拟或作为can的委婉形式。

9. can表示“能够”时与短语be able to同义，但can只用于一般现在时或过去时，而后者可用于各种时态。另外，can表示个人有某种能力，而be able to表示某人通过努力、克服困难做成某事，相当于succeed in doing sth.；叙述过去事实时，最好用was / were able to，因为could只表示过去具有某种能力。

10. can / could + have done在肯定句中表示“本来可以做而实际上没做某事” ；在疑问句或否定句中表示对过去行为的怀疑或不肯定,表示推测。 You could have done better, but you didn’t try your best. 你本来可以做得更好，但你没努力。 He can’t have been to that town. 他不可能去过那个城。

11. may (1)表示可能性，常用于肯定和否定句中 It may be true. (2) 表示请求、许可，多用于肯定和疑问句中 May I ask you a question? (3) 表示愿望 May you be happy all your life. might 比 may 语气更委婉 may/might表示推测时，表示对现在或将来要发生的事情把握不大。

12. might / may have done表示对过去发生的动作进行的可能性推测。 He may have gone to the clinic. 他可能去医务室了。 He might have read about the news in the newspaper. 他可能已经从报纸上知道这个消息了。

13. will / would 1. 表示意愿，will表示现在的意愿，would表示过去的意愿。 Go where you will. She asked if I would go with them. 2. 表示征求意见或提出请求，主要用于第二人称的疑问句中，will和would均可用，would此时并不表过去，而表示委婉语气。 Would Sunday night suit you? Will / Would you please post the letter for me?

14. 3. 表示习惯和倾向性 will表示现在的习惯，would表示过去的习惯。 Oil will float on water. When he was a child, he would often go skiing. 4. 表示预料或猜想will用于谈论现在，would可用于谈论过去，也可用于谈论现在(语气较委婉)。Ask him. He will know.     Every family would have some sort of trouble. I thought you would have finished it by now.

15. shall / should 1.在陈述句中,shall用于二、三人称表示允诺、警告、命令、决心等。 You shall do as I say. (命令) Nothing shallstop me doing it. (决心) Tell him that he shall have the book tomorrow. (允诺) 2.在疑问句中, 用于一、三人称，用来表示请求或征求意见。 Shall I open the window for you？（征求意见） Shall he fetch some water for you？（请求）

16. 3.should常表示劝告、建议、命令。 Young people should learn how to use computers. 4. should have done表示责备或批评,意为“本应该…但” You should have told her the truth earlier. She shouldn’t have left without saying a word. 5. should用于可能性推测时, 表“应该，很可能” They left at 5:30. Theyshouldget there now.

17. 高考真题 1. — Shall I inform him of the change of the schedule right now? — I am afraid you _______, in case he comes late for the meeting. （2011 福建） A. will B. must C. may D. can 答案：B 解析：根据下句后半部分“以免他开会迟到”，可知是告诉上句说话人“你必须立刻告诉”，故答案为B。本句的意思是：--- 我应该立刻通知他安排的变化吗？--- 恐怕你得立刻告诉他，以免他开会迟到。

18. 2. — I don’t really like James. Why did you invite him? — Don’t worry. He come. He said he wasn’t certain what his plans were. (2011 北京) A. must not B. need not C. would not D. might not 答案：D 解析：根据语境“他说他不太确定他的计划是什么”可知 “他可能不会来”。must not“不准”；need not“不必”；would not“不会”；might not“可能不”。

19. 3. Jack described his father, who ____ a brave boy many years ago, as a strong–willed man. （2010 安徽卷） A. would be B. would have been C. must be D. must have been 答案：D 解析：句意为“杰克把他的父亲描述为一个意志坚强的人，他的父亲多年前肯定很勇敢”用must have been表示对过去事情的肯定推测。

20. 4. You _____ buy a gift, but you can if you want to. （2010 湖南卷） A. must B. mustn't C. have to D. don't have to 答案：D 解析：don’t have to 意为“没有必要”，符合语境，句意为：“你没有必要买礼物，但如果你想买的话，你也可以买。”

21. 5. I have told you the truth. ______ I keep repeating it? （2010 江西卷） A. Must B. Can C. May D. Will 答案：A 解析： must 必须, 一定 can 可以, 能够， may 也许，will 意愿, 倾向性动作。前半句说我告诉你事实了, 这里用的是现在完成时, 表示过去的动作对现在造成了影响, 既然我已经说了, 我还必须重复一遍吗？

22. 6. I_______ have watched that movie — it’ll give me horrible dreams. （2010山 东卷） A. shouldn’t B. needn’t C. couldn’t D. mustn’t 答案：A 解析：句意应为“我本来不应该看那部电影的----它会使我做噩梦的。”表示“本来不应该做而做了某事”用shouldn’t have done, 所以A项正确。

23. Choose the best answers. • As he had heart attack, he was told that he • ____ continue the work.A. needn't B. may not C. mustn't D. can't • 2. An Englishman who ____ not speak Italian was once traveling in Italy. • A. must B. could C. may D. might • 3. I ____ like to make a suggestion. • A. could B. would C. must D. might • 4. I know things are hard with you, but you ____ try to get over the difficulties.A. can B. may C. must D. ought C B B C

24. 5. We hope that as many people as possible _____ join us for the picnic tomorrow.     A. may B. must    C. should D. can6. — I think I’ll give Bob a ring.    —You _____. You haven’t been in touch with him for ages.     A. will B. may     C. would D. should7. — Could I have a word with you, Mum?     — Oh dear, if you ______.    A. can B. must    C. may D. should D D B

25. 8. It is usually warm in my hometown in March, but it _____ be rather cold sometimes. A. must B. can C. should D. would 9. You don’t have to know the name of the author to find a book. You _____ find the book by the title. A. must B. need C. can D. would 10. Although this ____ sound like a simple task, great care is needed. A. must B. may C. shall D. should B C B

26. 11. You ______ be hungry already — you had lunch only two hours ago! A. wouldn’t B. can’t C. mustn’t D. needn’t 12. According to the air traffic rules, you ___ switch off your mobile phone before boarding. A. may B. can C. would D. should 13. She ______ have left school, for her bike is still here. A. can’t B. wouldn’t C. shouldn’t D. mustn’t B D A

27. Complete the following sentences using modal verbs. • You’ve been working all day. You ______ be very tired. • 2. I wonder who that is. It _____ be Lisa. She’s in the library at this time. • 3. It is a long time since we met last time. You _____ come and see us more often. • 4. I haven’t decided where I’m going for my holidays. I _____ go to Australia. must can’t should may

28. 5. My father’s birthday is coming. What _____ I get him? 6. Why don’t you try on this dress? It _______ look nice on you. 7. --- Who was the man talking with your teacher? --- I’m not sure. It ______ be her brother. 8. I don’t know when the guests be here. They _________ arrive at any time. shall will might will / could

29. Homework 1. Finish the exercises in Discovering Useful Structure. 2. Finish exercises in Using Structures in Workbook.