中考英语复习-情态动词.doc
第五讲 情态动词常考知识清单1.can,could,be able to的用法(1)can可以表示能力、可能性、允许等含义。could是can的过去式eg He can speak English.Anybody can make mistakes.You can park your car here.I could drive a car before I left school.(2)could也可以表示现在，用来委婉地提出请求或建议，回答必须用caneg -Could you show me the way? -Of course,I can.(3)can和be able to的区别can只用于一般现在时和一般过去时be able to用于各种时态(一般现在时，一般过去时，一般将来时.)注：could和was/were able to的区别could只表示具备某种能力was/were able to侧重经过努力成功做到某事Eg He was able to escape from Europe before the war broke out.2.may和might的用法may可以表示征求意见(用于疑问句)，也可以表示许可和可能性(用于陈述句)might可看做是may的过去式，也可以是一个单独的情态动词，表示有礼貌的请求或者可能。指可能性时比may 弱Eg May I come in?You may hand in your homework tomorrow.It may rain tomorrow.He asked if he might go home.He told me he might be late.3.must和have to(1)must表示“必须”，用来表示命令，强调说话人的主观意志。have to译为“不得不”，强调由客观因素决定。Eg I must go now,or Ill be late.The last bus has gone,so I have to walk home.(2)must的否定形式为mustnt,译为“禁止，不允许”。含有must的疑问句，其否定回答是neednt/dont have toEg You mustnt talk like that.-Must I leave now?-No,you neednt/dont have to.(3)must表示推测，译为“肯定，一定”，用于肯定句，否定句中必须用cant，译为“不可能”Eg She didnt look at me,she must be angry.She cant be serious.4.will和would(1)will表示一种意愿，用于一般现在时，would用于过去的情况Eg I will pay you as you like.She asked if I would go with them.(2)will/would用于第二人称的疑问句表示请求，would语气比will更委婉Eg -Will/Would you please open the window for me? -With pleasure.5.shouldshould表示一种义务或者推测Eg You should be more careful next time.(义务)She should pass his final exam.(推测)6.needneed表示“需要”，可用于肯定句、否定句和疑问句eg I need have a good rest.You neednt come if you are busy.Need I tell Tom what happened today?注：need也可以做实义动词need sth need to do sth dont need to do sth need doing sth=need to be done7.used to do表示“过去常常做某事”，否定形式为usednt to/didnt use to，其一般疑问句的形式是将used提到主语前或者用“Did .use to?”Eg We used to go there every year.Did you use to go to the library?They usednt to watch film.易错易混常考点1.must和have to的区别must侧重于个人意志和主观上的必要。have to侧重于客观上的必要，可用于一般现在时，一般过去时和一般将来时Eg I know I must work hard.My brother is very ill,so I had to send him to the hospital.I dont have any enough money with me,so Ill have to borrow some from my friend.2.may be和maybe的区别maybe做状语，常用于句首，may be做动词，一般用于句中。
