新东方戚乐:情态动词系列辨析
http://www.newdu.com 2025/09/18 03:09:31 新东方 佚名 参加讨论
情态动词 PART I 1. can, could (1)表示能力或客观可能性、请求或允许: Man cannot live without air or water. (2)表示惊异、怀疑、不相信: How can you be so careless! He couldn’t be over sixty. (3)表示对过去否定或疑问的猜测: Jack cannot (couldn’t) have been to China, has he? Can (Could) he have heard the news? (4)表示虚拟语气,用于肯定句,could have done,“过去能够干 某事而没干”。 I could have lent him money, but he didn’t ask me. Given more time, I could have done it even better. (5)表示“有时会”: Training alone can be dangerous. 2. may, might (1)表示推测“可能”: That may or may not be true. (2)对过去可能性的推测,may (might可能性更小)have done: She may not have seen the film. She might have had an accident. (3)表示虚拟语气“有可能干而没干”: She might have given you more help, but she didn’t. (4)表示祝愿: May you succeed in passing the exam! 3.must,have to (1)“必须”,“必要”: Soldiers must obey orders. You mustn’t talk like that. (2)肯定的猜测(不能用于否定或疑问):“一定”: He must be seventy now. He must be doing his homework upstairs. I think you must have made a mistake, didn’t you? He must have been doing his homework then. (3)(表示与说话人愿望相反及不耐烦)偏要 Just as I was hurrying to class, Mary must come, telling a long story. 4. need (1)“需要”,主要用于否定、疑问句。 You needn’t do it at once. (2)needn’t have done,“过去不需要干而干了”: You had enough time left. You needn’t have hurried. (3)特殊句型,“需要干某事”: The tree needs (wants, requires) watering (to be watered). 5.dare,dared (1)主要用于疑问、否定和条件句中: How dared they do such a thing? (2)可作实意动词:dare (to) do: He didn’t dare (to) go there. 6. shall, should (1)shall用于第一、第三人称疑问句中,征求对方意见: Shall I turn on the radio? (2)shall用于第二、第三人称陈述句中,表示允诺、警告、命 令、决心等。 You shall fail if you don’t take his advice. Nothing shall stop us from carrying out this plan. (3)should/ought to,“应该”: You should work hard at your lessons. (4)should(ought to) have done,“过去本来应该干某事而没干”; should not have done“过去本来不应该干某事而干了”,表示 委婉的批评: You should have come earlier. You shouldn’t have told her about it. You ought to have told me about that yesterday. 7. will, would (1)用于疑问句,表示请求、邀请: Will/Would you pass me the book? (2)“愿意”: If you will wait a little while, I’ll call the manager. (3)“总是”: He will often sit up all night. He would drop in on me on Sundays. (4)用于否定句,表拒绝,尤指物: We pushed the bus, but it wouldn’t move a bit. 8.used to “过去曾经……”,暗示现在不再如此: You used to smoke, usedn’t you (didn’t you)? PART II l 比较can /could 和be able to表示“能力”的含义 can / could 表示能力,可能 (过去时用could),只用于现在式和过去式(could); 而be able to可以用于各种时态。 l 比较can /could 和may表示“可能性、委婉的请求和许可”的含义 1、 may 与can 在表示可能性的时候,前者的可能性小于后者。may的委婉程度要比can深。May用于正式语体,can用于非正式,常见于“会话”中。 2、 may用于肯定的可能性推测,而表示不可能时则用can not。表示征求许可时用may,其肯定回答用can,否定回答用can not。 l 比较must 和 have to表示“必须”的含义 1、 must 与have to 都是强调要去做一件事的必要性,但究其原因,must,“必须”是强调自身的原因,表示说话人主观上的看法;而have to ,“必须”则强调外界的原因,表示客观需要,可以理解为“不得不”。 2、 have to有人称、数、时态的变化,而must却没有;在否定结构中要注意“语气”,don't have to 表示“不必”;mustn't表示“禁止”或“一定不要”。 例如:You don't have to tell him about it. Vs You mustn't tell him about it. l 比较need “情态动词”和“实义动词”的用法 1、 need作为情态动词,一般不用于肯定句,只能用于疑问句,否定句。例如: 1) Here comes the bus. So I needn’t take a taxi. (needn’t =need not) 2) Need I type this paper again? Yes, you must. / No, you needn't. 3) Should I tell Mike about it? No, you needn’t. I’ve told him already. 2、 need 作实义动词时,表示“需要,要求”,后面接名词或跟带to的动词不定式,(need + n. / to do sth. )。在构成否定句和疑问句时,要借助于助动词do。此时的need,既可以用于肯定句,也可以用于否定句和疑问句。 相关推荐: (责任编辑:admin) |
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