牛津深圳版英语七下《Chapter 5 Electricity》ppt课件.pptVIP

c ★Language 情态动词 情态动词不能单独作谓语动词，后接其它动词 原形做谓语，没有人称和数的变化。 表示能够或不能做某事用can 或 can’t A bird can fly . Fish can’t live without water. 2. 告诉人们必须或禁止做某事用must或mustn’t You must hand in your homework at once. You mustn’t talk loudly in public. 3. 表示请求或允许做某事may 或can May I come in ? Can I open the door ? 4 .谈论该做或不该做某事用should , ought to 或 shouldn’t , ought not to She should do her homework first . They ought to finish the work on time . they ought not to be late for school . ★★★Notes : 1、can 和 be able to的区别 : be able to 有 人称数和时态的变化。 I can come tomorrow . I will be able to come tomorrow. 2、 在回答must的疑问句时，否定回答常用 needn’t 或don’t have to表示不必，而不用 mustn’t 。 Must we stay here ? No, you need n’t . ( No, you don’t have to .) 3、 must be 表示肯定的猜测，意为“一定……” can’t be 表示否定的猜测，意为“ 不可能……” She must be a nurse . I saw her in the library just now .She can’t be here . 4、must have done 也表示肯定的猜测，意为“ 一定做过……” They must have cleaned the room . It’s so clean .他们一定打扫过房间了， 它这么干净。 Ⅰ.用适当的情态动词填空：。 1.__________you swim? 2.We ___________operate the machine last week, but we can operate it now. 3.Don’t worry. You _____ return me this book tomorrow. 4.He said if he _________ask me another question. 5.My grandma is ill. You _____ talk so loudly here . 6.I can’t play with you. I __________finish my homework first. 7.I__________ get up early tomorrow. 8.______________you please open the window? Can couldn’t may could can’t must must Could 9. Nobody ___________live without air. 10._________he speak Chinese ?Yes ,a little. 11. The book _________ be returned before Saturday. 12.__________I come in ?Yes ,please. 13. You ________give up smoking at once. It’s bad for your eyes. 14. Excuse me ._________I ask you a question? 15. __________you tell me where the station is ? 16. ______ I finish the work now ?No, you _________. You _____ do it this evening. 17. May I use your e-dictionary ? Sorry , you _________. I am using it now . 18