[中学联盟]浙江省杭州市塘栖中学高中英语必修三教学课件：U1P4 Grammar.ppt

Words like can, will, may, must, and a few others are called modals. Modal verbs help other verbs express a meaning or an idea. Some common uses of the modals are these: Ability: 1 He can speak English now. 2 He couldn’t speak English a year ago. 3 I’m not able to come to the game on Friday. Permission: All passengers may now board. We can board now. Obligation: You must fasten your seat belts. (strong) You should pay attention. (weak) You ought to pay attention. Possibility: 1 It may rain. 2 How could I forget an important thing like that? 3 He can’t/couldn’t have known the result. Meanings similar to those of the modals can often be conveyed by real verb forms: He has to……………………….=…must… is able to…speak English…=…can… is allowed to……………....=…may… is supposed to……………=…should… 1. can的主要用法是： ? A.?表示体力或脑力的能力: ? eg. The girl can dance very well. B.?表示说话者的推测﹑事物的可能性: eg. Can the news be true? C. 在口语中, can可以表示请求或允许: eg. Can I sit here? 2. could的主要用法是： A. could是can的过去式, 表示与过去 有关的能力和推测: eg. We all knew that the young man couldn’t be a doctor. B. could可以代替can表示请求, 但语 气较can客气、委婉: eg. Could you lend me your dictionary? Could I use your bike? 3. can和could接动词的完成形式，表示可能已经做某事。can用在否定和疑问句中, 表示不相信、怀疑等态度。 eg. They cant have gone out because the light is still on. may常用来表示： A. 表示请求、允许: 比can较为正式: ?? eg. May I come in? You may go now. B. 表示说话人的猜测: “也许” “可能”: 通 常只用于肯定句和否定句中。 eg. I believe the man is from England. But I may be wrong. The guest may arrive this afternoon. The road may be blocked. 这条路可能不通了。 The road can be blocked.