情态动词讲解 高一ppt.ppt

Grammar Modal verbs（情态动词）;How many modal verbs do you know?;;情态动词的特点：;can 与could 1.表示能力：会 在表示过去的能力时用could I can swim. 我会游泳 I could not read such a easy book when I was 7 years old. 我七岁时连如此简单的书都看不懂 2.表示允许，许可。常用在口语中 此时could不表示时态，而是表示比can语气上客气些 ----Could I use your dictionary?我可以用一下你的字典吗？ -----Yes, go ahead.可以，用吧（或Yes, you can.但不能说Yes, you could.) Can/Could you tell me the way to the zoo?你能告诉我怎么去动物园吗？ ;3.表示推测，用于肯定句（can罕见），否定句或疑问句。 但更常见于疑问句与否定句，在此种用法中，can 与could没有时态的区别，只有可能性大小的区别。can表示推测的可能性比could大。 Can he be ill at home?(他会是生病在家吗？) He cannot be at home.(他不可能在家) You mustnt smoke when you walk in the woods. You could start a fire.那样可能会引起火灾。 could/ can have done 表示对过去事情的推测 She cant have gone to school. Its Sunday. 4.表示理论上的可能性，指常有的行为或情形，意为有时会。 Peter can be really annoying . Peter 有时候会很讨厌 Accidents can happen to any drunken driver.醉酒的司机都有可能发生交通事故。;can的习惯用法 1.表示惊异，怀疑，不相信等态度，主要用于否定句和疑问词 How can you be so careless? 你怎么这么粗心？ 2.can but只好，最多不过 We can but do our best. 我们只好尽力而为 3.cannot too to 无论怎么样都不过分 You cannot be too careful to cross the road. 过马路时 你再小心也不过分;can 与be able to的区别 1.can 表示能力时，和be able to相当，许多场合都可以互相替换。但当叙述过去经过一番努力才能完成的事情或前面有特殊说明，你有能力，只能用be able to. Can you speak any foreign languages?你会说外语吗？（正） Are you able to speak any foreign languages?（正） The fire spread the building quickly but everybody could escape.(误) The fire spread the building quickly but everybody was able to escape.（正） 大火迅速蔓延到整栋大楼，但大家都逃出来了。 can表示又能力做，但不一定做。be able to在这里=manage to;2.be able to比can有更多的形式 No one could answer the question.没人能回答这个问题。 =No one was able to answer the question. When he grows up, he will be able to support his family. 当他长大了，他将可以养家糊口。 Frank is ill. He hasnt been able to go to school for one week. Frank 生病了，一星期没能去上学了 Im sorry for not being able to help you in time. 对不起，不能及时帮你的忙 ;may 和might;肯定回答，Yes, please. Certainly. Yes, of course. Sure Go ahead, please. 否定回答 No, you cant.(最常见) No, you mustnt(表示强烈禁止的意思) Please dont. Youd better not. I dont