9B unit 1语法.ppt

牛津9B Unit 1 Grammar can, could, may, might都可以用来表示请求或给予许可。但用法上有一些区别： 1. can与could can常用于口语中，表示非正式的请求，请求对象一般是家人或朋友。如： —Can I borrow your bike, Simon? 西蒙，我可以借一下你的自行车吗？ —Of course. 当然可以。 —Can I have some milk, Mum? 妈妈，我可以喝点牛奶吗？ —Yes, you can. 好的。 could是can的过去式，在口语中，could常用来代替can向对方更委婉地提出请求，用法上比can正式，可以用于向老师或长辈提出请求，这时could不表示过去，回答一般还是用can。如： a) —Could I use your computer, please? 请问，我可以用一下你的电脑吗？ —Yes, you can. 可以。 b) —Could I hand in our homework later, Mr Lin? 林老师，我可以稍后交作业吗？ —No, you can’t. 不，不行。 2. may与might may也可以用来征求对方意见，意为“可以”，相当于could，用法也比can更正式，更礼貌，一般用于向陌生人或所尊敬的人请求许可。如： —May I ask you a question? 我可以 问你一个问题吗？ —Yes, please. 可以，请问。 b) —May I come in, Mr Wu? 吴老师， 我可以进来吗？ —No, you may not. 不行。 might是may的过去式，它也可以用来表示征求对方意见，不过很少用。might在语气上比may更婉转，但不如may表现得那么自信，这时might不表示过去时态，肯定回答时通常用may。如： a) —Might I join you? 我可以加入你们吗？ —Yes, you may. 可以。 b) —Might I have a look at your new plan? 我可以看一下你的新计划吗？ — No, you may not. 不，不行。 Exercises: 1. —May I go surfing alone this afternoon, Dad? —No, you ____. It is dangerous. (2005 江苏南京) A. may not B. can’t C. needn’t D. don’t 2. —Can I get you a drink? —____. I have already got one. (2005 甘肃) A. That’s very nice of you. B. No, you don’t have to. C. Yes, please. D. With pleasure. 3. Lin Ling’s mother wanted to know ____. (2005 四川) A. if she studied hard at school B. how did she study at school C. what did she study at school 4. Do you want to know ____in the future? A special mirror invented by the French scientists can help you. (2006 山东莱芜) A. what you will look like B. what will you look like C. how do you look like D. how you look like 5. It is said that the gravity on Mars is only about ____ of the gravity on Earth. (2006 江苏苏州) A. three-eighths B. third-eight C. three-eights