新人教必修3_Unit1_Grammar情态动词].ppt

* * 情态动词 ( modal verbs) 情态动词主要用来表说话人的看法、意愿、 态度等。从用法上来说，它有如下几个特点： 1. 情态动词本身都有一定的词义； 2. 情态动词不能单独做谓语； 3. 情态动词没有人称和数的变化； 4. 情态动词后接不带to的不定式（除ought to 和used to 外），即接动词原形。 一、定义 1) Some of us can use the computer now, but we couldn’t last year. 2) The new-built theatre can seat 1500 people. 3) Can this news true? 4) I though what he said could not be true. 5) Can/Could I use your dictionary? 6) Could you lend me a hand? 1). 表能力, 常译为“能，会”， could指过去时间。 3). 表示“请求” “允许” (表请求时，口语中常用 could 代替 can 使语气更委婉，回答时用can) 2). 表示推测，意为“可能”“或许”，用于疑问句或否定句 1. can 与could 二、基本用法 4). 表示“许可”，可与may 换用。 You can go home now. 5). 用于疑问句或否定句或感叹句中时，表猜测、惊讶、 不相信等，“可能、能够”。could猜测的可能性更小。 I believe that he cant be so rude. He is an honest man, he couldnt be telling lies. 6). can’t/ couldn’t +have + done 不可能 表示对过去情况的否定推测 Susan can’t have written a report like this. 7). could + have + done “本应该” 表示对过去能做而未做的事情感到惋惜，遗憾 It’s a pity. Your class could have got the first prize. Michael ____ be a policeman, for he’s much too short. A. needn’t B. can’t C. should D. may 2. Mr. Bush is on time for everything. How ____ it be that he was late for the opening ceremony? A. can B. should C. may D. must 3. ---- I stayed at a hotel while in New York. ---- Oh, did you? You ____ with Barbara. A. could have stayed B. could stay C. would stay D. must have stayed My sister met him at the Grand Theater yesterday afternoon, so he ____ your lecture. A. couldn’t have attended B. needn’t have attended C. mustn’t have attended D. shouldn’t have attended B A A A 2. can 和 be able to 1) can 只有现在时和过去时could，而be able to 有更多 的时态变化。 2) can 一般指只身具有的能力，be able to 表示经过 一段的时间努力后所具有的 能力，相当于manage to do或succeed in doing. This time I failed in the exam, but Ill be able to pass the exam next time. 3) 在否定结构中，was/were be able to和could 没有区别。 She ran fast but she c