英语语法助动词.ppt

ought to的用法 1. ought 没有词形变化，通用于所有人称，否定式为ought not(oughtn’t) to (1)表示理应做的事，应该做的事，意为“应该，应当” You ought to study hard. 你应该努力学习。（=It’s your duty to study hard. ） (2)表推测，译为“应是，应该，会是” It is already twelve o’clock .Lunch ought to be ready.现在已经是12点了，午饭应该好了。 2. ought to have+过去分词常表示一个与过去事实相反的情况，肯定式表示“应该做某事而没有做”，否定式表示“不应该做某事但却做了” It is too late. You ought to have taken the chance then.现在太晚了你本该当时就抓住机会的。（But you didn’t.） His wife is vain and selfish. He oughtn’t to have married her.他妻子虚荣自私，他本不该娶她的。 助动词 协助主要动词构成谓语动词词组的词叫助 动词（Auxiliary Verb）。被协助的动词称作主要动词（Main Verb）。 助动词自身没有词义，不可单独使用。如： He doesnt like English.他不喜欢英语。 （doesnt是助动词，无词义；like是主要动词，有词义) 什么是助动词？ 分类及简介 助动词分为：基本助动词，情态助动词，半助动词。 基本助动词：be，do，have 情态助动词：shall, will, should, would，could 半助动词：以be为中心成分，以have为中心成分，以seem为中心成分。 助动词be的用法： 1)be +现在分词，构成进行时态。如： They are having a meeting. English is becoming more and more important. 2)be + 过去分词，构成被动语态。如： The window was broken by Tom. English is taught throughout the world. 3)be + 动词不定式，可表示最近、未来的计划或安排。如： ?He is to go to New York next week. ?We are to teach the fresh persons. 一、基本助动词 助动词have的用法: 1)have +过去分词，构成完成时态。如： He has left for London. By the end of last month, they had finished half of their work. 2）have + been +现在分词，构成完成进行时。如： I have been studying English for ten years. 3）have + been +过去分词，构成完成式被动语态。如： English has been taught in China for many years. 助动词do 的用法: 1）构成一般疑问句。如： Do you want to pass the CET? 2）do + not 构成否定句。如： He doesnt like to study. In the past, many students did not know the importance of English. 3)构成否定祈使句。如： Dont be so absent-minded. 说明： 构成否定祈使句只用do，不用 did和does。 4)放在动词原形前，加强该动词的语 气。如： Do come to my birthday party. I did go there. 5)用于倒装句，例如： Never did I hear of such a thing. Only when we begin our college life do we realize the importance of English. 只有在开始大学生活时我们才认识到英 语的重要性。 说明：引导此类倒装句的副词有never, seldom, rarely, little, only, so, well等。 6)用作代动词，例如： — Do you like Beijing? — Yes, I do. （do用作代动词，代替like Beijing.） He knows how