英语情态动词5.pptVIP

(2) 表猜测，“应该”，“理应” He must be home by now. (断定他已到家) He ought to be home by now. (不十分肯定) need和dare ①情态动词，主要用于否定句和疑问句。 ②实义动词，各种句式。 ① 情态动词 +V原 1) need You?needn’t?telephone?him?now.??? Need I telephone him now? 2) dare She?dare?not?go?out?alone?at?night.? How?dare?you?say?I’m?unfair??? dare need —Dare you tell her the truth? —Yes, _________. —No, __________. I dare I daren’t 注意对need问句的回答: --Need I finish the work today? --Yes, ________________. No, ________________. No, ________________. you must you needn’t you don’t have to --Must we do it now? --No, you __________. --No, you __________. needn’t don’t have to ②用作实义动词 1) need You?don’t?need?to?do?it?yourself.??? Do you need to do it yourself? A job like nursing needs patience and understanding. ※ need doing = need to be done 2) dare Only a few journalists dared to cover the story. He did not dare (to) look up. (肯定句中dare to do , 否定句中可以省略to) I dare say he’ll come again. （I dare say… 为固定习语）? 情态动词 + have done 这是历年高考热点之一， 可表示“推测、责备、怀疑” 等多种意义。 表示推测——情态动词的重要用法 肯定的推测 可能的推测 否定的推测 疑问的推测 must 对将来 对现在 对过去 情态动词 may, might can’t, couldn’t can, could + V. + V. + have done 常见must be + be doing + V. + V. + have done + be doing 可以用not表示“可能不” +V. + V. + have done + be doing + V. + V. + have done + be doing 一、表示对过去事情的推测或估计 1. must have done “想必或肯定已经做了某事” eg: The ground is rather wet, so it must have rained last night. 2. may/might have done “可能/大概已经做了某事” eg: Tom may have gone to shanghai, but I still not sure about it. 3. can’t/couldn’t have done “不可能已经做了某事” eg: The ground is very dry, so it can’t have rained last night 注：在疑问句中 can/could 表示对过去情况的疑问性