情态动词语法

1、 Lesson 40 Unit ReviewModal Verbs 情态动词Modal Verbs(情态动词):情态动词有一定的词义，但词义不完全，不能单独作谓语，必须和行为动词连用，主要是来表示说话人对某一动作或状态的态度和看法，情态动词后面跟动词原形，一般没有人称和数的变化。初中阶段应掌握的情态动词主要有： can/could may/might must need should would have to can, may, must, need, should can: 1) 表能力 2) 表客观可能性（通常用否定） 3) 表允许（与may 意思相近） may: 1) 表示客气的请求

2、2) 表示许可 3) 表示一件事或许会发生 must: 1) 表必须要做的事 2) 表肯定的猜测 should: 表示劝告、建议（译成应该） need 表示需要 1. can: 1) 表能力 We can speak English well now. 2) 表客观可能性（通常用否定） The news cant be true. 3) 表允许（与may 意思相近） Can I have a try? could表比较委婉客气地提出问题或陈述看法 Could you please tell me the way to school?*2. may : 1) 表示客气的请求 - May I co

3、me in? - Come in, please. - May I borrow your pen , please? - Certainly! - May I have a piece of paper? - Of course. 3) 表示一件事或许会发生 I may be a sailor(水手) when I grow up. What may happen?2) 表示许可 You may have a rest. 3.must : 1) 表必须要做的事 We must do everything step by step. You mustnt talk loudly in the

4、library. - Must I clean the classroom now? - Yes , you must. / - No , you neednt. 表肯定的猜测 This must be your room. He must be asleep. He cant be awake now. 4.need 作情态动词，表“需要”，主要用于否定句和疑问句。- Need he go so soon?- Yes, he must.- No, he neednt.We neednt hurry.5. should: 表示劝告、建议（译成应该） We should read English

5、 every morning. We should obey(遵守) the traffic rules. We shouldnt stay up late every day. 使用情态动词需要注意的问题： 情态动词一般没有人称和数的变化,不能单独作谓语,需与后面的动词原形一起构成谓语。2. can 提问的句子，肯定回答用can，否定回答用cant。3. 用 may 提问的肯定回答一般用sure, certainly, of course, Yes, please, 避免用may。 否定回答一般用mustnt , cant , 也可以用may not. - May I smoke here?

6、 -No, you mustnt. *4.回答must引出的问句时,肯定回答用must，否定回答一 般不用mustnt,而要用neednt或dont have to。如: - Must we hand in our exercise books today? - No, you dont have to.(No, you neednt.)6.作为情态动词，need一般不能用于肯定句中，仅用于 否定句、疑问句和条件状语从句中。 You neednt come so early. - Need I finish the work today? - Yes,you must. / No, you n

7、eednt.5. 回答need引出的问句时，肯定回答用must，否定回 答用neednt。7. 表示能够意义的can与be able to的区别。在表示能力时,can与be able to的意义差不多,有时两者可换用,但表示经过努力、设法做成某事时,要用be able to,不可用can。 be able to 有人称和更多时态的变化。 如: Youll be able to read it before long(不就以后).Will you be able to come tonight? = Can you come tonight?8.表示“不能”意义的cant与mustnt的区别。如

8、：cant表 示“不能”,意指没有能力;mustnt表示“不能”，意指“禁 止；不允许”。 The baby is asleep. You mustnt make any noise. The boy is so tired that he cant go any further.9.表示“必须”的must与have to的区别。must表示说话人 的主观看法；而have to则表示客观需要。mustnt意为“ 不可以;不允许；dont have to意为不必。如: My father had to work when he was ten years old. The play is not

9、 interesting. I really must go now.11.在回答一般疑问句could引导的表示请求的时，不能用 could回答，而要用can。如： - Could you tell me how to get to the hospital? - Of course,I can.12.“may you+动词原形”放在句首，意为“祝愿；但愿”。 May you succeed! 祝你成功！ May you be happy every single day. 祝你天天快乐。10. must 表示猜测比may表示的要肯定得多，而且只有在 肯定句中能这样用。表否定的猜测则用cant

10、 。Can ?May .?Must ?Need ? cancantmay/cancertainly/sure/of course/Yes, please.cant mustnt may notmust needntdont have tomust neednt 特别强调：用适当的情态动词填空：I _ go almost anywhere on foot. At first, only rich people _ buy cars. - Can you ride a bike ? No, I _.- _ I go home now? - No, you _ stay here. - _ I do

11、 the exercises today? - No, you _. You _ do them tomorrow. 6. The red light is on. We _ stop. 7. You _ learn to drive. It will be very useful. 8. My eyes are not very good. I _ to wear glasses.9. I _ like to see hoverboards. 10. _ you tell me the way to the post office? cancould cant Can/May must Mu

12、st neednt can/may must should have to would Can/Could Correct the mistakes:- Must I finish my homework today? - No, you mustnt .2. - Need I go home now? - Yes, you need. 3. This book mustnt be mine because my book is at home. _must _cant neednt Multiple choice：Im sorry I _ finish my homework on time

13、. A. cant B. mustnt C. neednt D. mayWhen the lights are red, the traffic _ stop. then you _ cross. A. mustcan B. have to must C. cancan D. shouldshouldYou _ return the dictionary now. You _keep it until next week. A. cantcan B. mayshould C. needntmay D. may mustYoud better go and ask the policeman.

14、He _ know how to get to the shop. A. can B. may C. would D. needAACB5. - Must we finish our homework now? - No, you _. A. must B. neednt C. cant D. may not6. You made so many spelling mistakes. You _ be more careful next time. A. have to B. should C. can D. may7. -Must I turn off the light now? -Yes, you_. A. need B.should C. must D. may8. You _talk when you are driving. Its dangerous. A. can B. cant C. should D.shouldnt9. He doesnt come to school on time. He _ be ill. A. can B. cant C. must D. mustnt10. Lisa has gone to Beijing. The young lady over there _ be her. A. can