1、Unit 4 Road safety (Grammar time ) 练习单 Task 1. Look and say. Task 2. Important and difficult points.(情态动词用法总结) 情态动词有 can、should、must 等，它们后面都是加动词原形。 1. can 的用法： （1）表示能力、体力、知识、技能等，能、会。Eg: I can swim well. （2）否定形式 cant , 不能、不会、不可以。Eg: I cant skate. （3）表示请求和允许，可以。Eg: Can I go in? 2. should 的用法：（1） 表示责任、
2、 义务或建议， 应该、 应当。 Eg: He should drink water. （2）否定形式 shouldnt, 不应该，不应当。 3. must 的用法： （1）表示必须。 Eg: You must stop here. （2）否定形式 mustnt 表示强烈禁止。Eg: You mustnt swim here. ( 3) 表示推测，只用在肯定句中，有“一定，想必”之意。 Eg: The light in her room is still on. She must be at home now. 情态动词在肯定句、否定句、一般疑问句和特殊疑问句中的用法： 肯定句：主语+情态动词+
3、动词原形+其他。 否定句：主语+情态动词+not+动词原形+其他。 情态动词 语气由弱到强 should/shouldnt can/cant must/mustnt How can you cross the road safely? We must. What must you not do on the road？ We mustnt. 一般疑问句：情态动词+主语+动词原形+其他？ 特殊疑问句：特殊疑问词+情态动词+主语+动词原形+其他？ Task 3. Exercise 1. I must _ (finish) my homework before dinner. 2. In publi
4、c, you _ (must) smoke. You can _ (smoke) in the smoking room. 3. _ (should) Liu Tao speak _(loud) in the library? No, he _.(should) 4. -Can Nancy _ (see) the traffic lights? -She mustnt _ (cross) the road now. 5. What must they not _ (do) on the road? They mustnt play on the road. 6. Where should Tom _ books? He should _ in the study. (read)
