情态动词一、情态动词的定义：情态动词有词义，但它不能单独作谓语，它必须和其他动词一起构成谓语。
情态动词没有人称和数的变化；它的后面必须跟动词原形。
三．用法特点⑴它们必须与其他动词连用，即：肯定：情态动词＋动词原形：He can swim.否定：情态动词+not+动词原形：He can not(can’t)swim.一般疑问句：把情态动词提前：Can he swim?Yes,he can./No,he can’t.表示说话人对所述动作的看法，如需要、可能、意愿或怀疑等。
⑵情态动词没有人称和数的变化，即第三人称单数不加-s，有些情态动词有时态的变化⑶在意义上，情态动词具有“多义性”。
例：can既可表示能力，又可表示可能、允许等意义。
四、情态动词的用法及主要句型：1、Can I help you? ——Yes, please. / No, thanks.2、Can + 主语+ 动词原形? Yes, ～can. No, ～can’t.3、Can I borrow（借用）your book?----Yes,of course.4、Can I write on the book? ------No, you can’t\mustn’t.5、Could \Can you help me?---- Yes,of course.\Certainly.\ Sure.6、Could \Can you tell me the way to the zoo?7、May I come in ?----- Come in, please.8、May I sit here?----- Yes, please.\Sorry, please don’t.9、May I have some Coke?---- Yes, of course.10、May/ Could / Can I speak to Tom? -----Speaking. Who’s calling?11、should 、shouldn’t 表示劝告：1) He should get up early.2) She shouldn’t play computer game too much.12、Should +主语+动词原形? Yes, ～should.\ No, ～shouldn’t.13、表示建议“你愿意…吗”Would you like to go shopping with me?-----Yes, I’d love to. /I’d love to. But I’m busy now.14、就餐用语Would you like something to eat\drink? ----Yes, I’d like…15、shall用于第一人称(I, we), 可以表示“将”和表示建议“……好吗?”1) Where shall we have dinner?2) Shall we go fishing? -----All right. \OK. \Good idea.16、Must + 主语+ 动词原形? ---Yes,～must.\No, ～needn’t.情态动词练习一．按照要求改写句子1. I can run fast.I ________ ________ fast. (否定句)2. You must return the book now.（一般疑问句）________ I return the book now? No, you ________.3. He can play basketball well. （一般疑问句）_______ he ______ basketball well?4. They must take the books out of the room. （否定句）They ________ ________ the books out of the room.5. He should get up early. (否定句)He _______ get up late.6. Daniel must watch TV every evening.(改为否定句)___________________________________________________7. I can’t do my homework every day.(改为肯定句)________________________________________________________8. You’ll need your book and pen..(改为否定句)_______________________________________________________9.We shall like playing computer games.(翻译句子)________________________________________________________10. She should go to school every morning.(改为否定句)_______________________________________________________11. He can speak English very well.(翻译句子)__________________________________________________________12. Would you like to drink coffee?(肯定回答)________________________________________________________13. She can walk quickly. (否定句)14. They can paint the wall well. （一般疑问句）________________________________________________________15. Tom must carry the box into the room. （否定句）________________________________________________________16. She should reach the station early. (否定句)________________________________________________________二．单项选择。
（）1. you like some milk ? A . Would B. Could C . Can （）2. We pick the flower in the park. A. can’t B. don't C. mustn’t ( ) 3.We should more trees, and we shouldn’t cut any trees.A. plantB. plantingC. plants( ) 4.May I have some coffee?A.Yes,you have.B. Yes,you can.C. Yes,certainly.( ) 5.Shall we visit the factory?A.Yes,we do.B.Yes, we shall. B.All right.( ) 6.Would you like something to eat?A.Yes,we would.B.Yes, I’d like some cakes.C.Yes, of course.( ) 7.What can I do for you?A.Yes,you can.B.No,I can do it.C. Yes.I’d like so me oranges.（）8. you like some bread ?A . Would B. Could C . Can（）9. We throw the waste in the zoo.A. aren’t`B. don'tC. mustn’tA.Yes,you have.B. Yes,you can.C. Yes,certainly. ( ) 11.Would you like some tea?A.Yes,thank you..B.Yes, please. B. No, here you are.. ( ) 12.Can I help you?A.Yes,you can.B.No,I can do it.C.Yes.I’d like some orange s. ( ) 13. May I your eraser ?A useB hasC using( ) 14. Can she high?A jumpsB jumpingC jump( ) 15. What should Amy for her mum?A buysB buyingC buy( ) 16. They may in the libtary.A readB readingC reads( ) 17. I would like shopping with you.A goingB to goC go( ) 18. What will Zhou Lin ?A doB doingC does( ) 20. They must .A friendlyB are friendlyC be friendly。