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1、人教课标版 高一 必修 3 情态动词的语法特征 1) 情态动词 不能单独做谓语, 除ought 和 have 外, 后面只能接不带to 的不定式。 2) 情态动词没有人称, 数的变化, 但有些情 态动词, 如can、will也有一般式和过去式的 变化。 3) 情态动词的“时态”形式并不是时间区别的 主要标志, 不少情况下, 情态动词的现在式形 式和过去式形式都可用来表示现在时间、过 去时间和将来时间。 1) can的主要用法是： A. 表示体力或脑力的能力： eg. The girl can dance very well. B. 表示说话的推测 事物的可能 性等: eg. Can the n
2、ews be true? C. 在口语中, can可以表示请求或 允许: eg. Can I sit here? can 和could： 2) could的主要用法是： A. could 是can的过去式, 表示 与过去 有关的能力和推测: eg. We all knew that the young man couldnt be a doctor. B. could可以代替can表示请求 , 但语气较can客气、委婉: eg. Could you lend me your dictionary? Could I use your bike? 3) can和could接动词的完成形 式，表示可
3、能已经做某事。can用 在否定和疑问句中, 表示不相信、 怀疑等态度。 eg. They cant have gone out because the light is still on. may 和might ： may 常用来表示： A. 表示请求、允许;比can较为 正式: eg. May I come in ? You may go now. B. 表示说话人的猜测: “也许” “ 可能”: 通常只用于肯定句和否定 句中。 eg. -I believe the man is from England. -But I may be wrong. The guest may arrive
4、this afternoon. 在肯定句中，may 的可能性 比can 高，may 表示现实的可能性 ，can 表示理论上的可能性。如： The road may be blocked. 这条路可能不通了。 The road can be blocked. 这条路可能会是不通的。 在疑问句中，表示可能性用can 。 如：Where can he be? 他会在 哪呢？ C. 表示祝愿;但语气较正式: eg. May you succeed! May you have a good journey! might 的用法有: 多在间接引语中表示过去的 可能和允许。如: She said that
5、he might take her bike. 她说他可以拿她的自行车去 用。 除了在间接引语中以外， might 一般不表示过去的可能或者 许可。如要表示过去的可能可以用 could, 表示过去的许可可以用was( were) allowed to 或者 had permission to 。 表示现在的可能，其可能性要 比 may 小。如： She might go home tomorrow. 说不定他明天会回家。 表示现在的许可, 语气比may 较委婉, 一般用于疑问句(包括间接 疑问句), 不可用于肯定句或者否定 句。 如: Might I have a word with you?
6、 我可以和你说句话吗？ will和would： 1. will是助动词或是情态动词？ will用于构成将来时是助动词 。用于表示“意志”“决心”“请求” 是情态动词。would亦同理。 eg. I will tell you something important. 我要告诉你一些重要的事 。 （助动词） Will you tell her that Im here? 请您告诉她说我在这儿，好吗 ？ （情态动词） 2. 在疑问句中用于第二人称，提 出请求或询问。 eg: If you want help - let me know, will you? 如果你需要帮助, 让我知道, 好吗? W
7、ill you type this, please? 请打印这个, 好吗？ Wont you sit down? 请坐下, 好吗？ 3. would比will客气委婉。 eg: Would you help us, please? 请您帮助我们，好吗 ？ （表请求） Id go there with you. 我要和你一块到那儿去。 Teacher wouldnt allow it. 老师不会允许这件事。 （表意愿） （表许可） shall和should： 1. shall用于构成将来时是助动词 。 shall用于征求对方的意见，表 示 “决心” 是情态动词。 eg: Perhaps I sh
8、all pay a visit to England this winter. 可能今年冬天我会去英国 观光。 （构成一般将来时, 助动词 ） Shall we go by train, Mom? 妈妈，我们乘火车去好吗？ （用于征求对方的意见，情态 动词） I shall go at once. 我必须立即去。 （表 “决心”，情态动词） 2. should表示义务、建议、劝 告，意为 “应该”。 “should+ have+过去分词” 表示本应该在过去做但没有做。 eg: You should keep your promise. 你应该遵守诺言。 She should have pass
9、ed the exam. 她应该通过考试的。 must和 have to 1.must用于一般问句中,肯定回答用must 否定式用 neednt或dont have to，做 “ 不必”,mustnt表示“禁止，不允许” Must I finish all assignments at a time? Yes, you must. No, you neednt. I dont like this TV set. We must buy a new one. There was no more bus. They had to walk home. 2.表示“必须”这个意思时，must 和 ha
10、ve 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。 You must be the new teacher. He must be joking. There is nobody here. They must have all gone home. 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 He must come and worry her with question, just when she was busy co
11、oking the dinner. Of course，after I gave her my advice，she must go and do the opposite. 4. must表示“偏要, 硬要”, 指做令人不快 的事情 2. A: _ Xiao Feng find the origin of Easter from that book? B: No, he _. 1. A: _ you like to go to a special event with us on Saturday? B: Yes, I _ _. Would d like to go with you on
12、Saturday Could couldnt find it Exercise 3. A: _ I go with my friend to the harvest festival? B: Yes, you _ _. 4. A: If I want to be a doctor _ I study science? B: Yes, you _. should study science May may go ( with your should friends ) 5. A: He is very handsome. _ he play the role of the prince? B:
13、No, he _ _. cant play the role of the Can prince 6. A: The neighbour s children are older this year. _ they stop playing tricks at Halloween? B: Perhaps, they _ _. _ _ _. Mightor Should might stop or should stop playing tricks playing tricks at Halloween at Halloween 1. -_ I go out to play, mum? -No
14、, you_. You should do your homework first. A. Might; wouldnt B. May; had better not C. Must; mustnt D. Need; mustnt B 练习坊 I. Choose the correct answer. 2. -Where is Emma? -I cant say for sure where she is, but she_ be out shopping. A. can B. should C. must D. mayD 3. The room is in a terrible mess;
15、it _ cleaned. A. cant have been B. couldnt be C. may have been D. would be A 4. How _ you say that you really understand the whole story if you have covered only part of the article? A. can B. must C. need D. may A 5. There _ be any difficulty about passing the road test since you have practised a lot in the driving school. A. mustnt B. shant C. shouldnt D. neednt C 6.-There were already five people in the car but
