语法专题情态动词的用法(补充)47

语法专题情态动词的用法补充1、情态动词考前须知1、Could I borrow your book? Yes. Of course you can.2. Would you like to do it for me ? Yes. I will.2、推测语气(1) 对现在或将来情况推测：must +动词原形。must只能用于肯定。否认和疑问分别用cant和can。He must tell a lie. Can he tell a lie ? He cant tell a lie.*Must-should/ought to may-might/could+do 可能性依次减弱(2) 对过去情况推测：must (may, might)+完成时。You must have met him before. mustmaymight可能性依次减弱must只能用于肯定句，译成“一定。否认和疑问分别用cant / couldnt和can / could。Could /Can it have happened last night ?It couldnt/cant have happened last night.3、表猜想语气的反意疑问句的构成He must be reading, isnt he?You must do it yourself, dont you?He must have gone over the article, he?It must have rained last night, it?4、 be able to must would can have to used to do need mustnt dare dont have to=neednt may/might do/have done 不妨; 还是为好5、Shall1用于第一人称表将来。I shall go to work after I have finished school.2用于一、三人称疑问句、表征求对方意见或向对方请求。Shall he come in? Come in, please.3用于二、三人称，表示保证、承诺、威胁、警告。You shall be punished if you insist on doing it this way.6、should1预测、可能。They should be here by now.2说话人的感情。如惊奇、愤怒、失望等、“竟然 You cant imagine that well-behaved gentleman should be so rude to a lady.7、情态动词+have done1对过去情况推测。 must/may/might have donecant/couldnt/may not/might not have donecan/could have done?2译成“本could/should/need have done.You should have come here five minutes earlier.3虚拟语气与过去事实相反的主句If you had followed my advice, you wouldnt have been defeated.