背出情態(tài)動詞要點

1、情態(tài)動詞 Modal verbs情態(tài)動詞表示說話人對某一動作或狀態(tài)的態(tài)度，認為可能、應(yīng)當(dāng)、必要等等，情態(tài)動 詞沒有人稱和數(shù)的變化。1can 和 could (could 是 can 的過去式。 )(1) . 表示“能力 ”、“許可”、“可能性 ”(用于疑問句或否定句中) 。Can she drive a bus?Can it be trueThe teacher can't be in the office.?(2). could 可以用來比較委婉地提出問題。Could you help me with my English ?(3) can 和 be able to 意思上沒有區(qū)別

2、.was / were able to do=succeeded in doing sth. 表示過去成功做成某事 .A fire happened to the hotel last night but luckily everyone was able to get out.2 may 和 might (might 是 may 的過去式。 )(1) 表示允許或征詢對方許可，有 可以"的意思。否定式 may not,也可用must not = mustn '但常用 mustn't 來表示 “不可以 ”、“禁止 ”、“不允許 ”等意思。May I watch TV a

3、fter supper?Yes, you may.No, you may not (mustn't) .在請求對方許可時，Might I更禮貌 一些。Might I have your name ?(2) 表示可能性, “或許 ”、“可能 ”(用在肯定句中 )。 Might 表示語氣更加不肯定。He may / might come today 3.must 和 have to(1) 表示“必須”、“應(yīng)該 ”。否定式 must not (mustn '表示 不許可” 不準” 禁止"等。Everybody must obey the rulesYou mustn'

4、;t lend it to others回答“must'的問句時，否定式 needn't，表示 不必”不用 must not,Must I be home before eight o'clock? Yes, you mustNo, you needn't (You don ' t have to.) ( 2)表示“偏偏,總是'Why must you always leave your dirty clothes in the bedroom?Why must it rain on New Year 'Day?(3) have to 表

5、示 “必須'、 “不得不 ',have to表示客觀需要。have to有更多的時態(tài)形式。must表示的是說話人的主觀看法。You must work hard at your lessons主觀看法 )I have to go now. (客觀需要 )(4) 表示推測“一定' “必定'(用在肯定句中)The teacher must be in his office.He must be doing his homework now.4need 和 dare(1)need表示 需要” 必需”。常用在否定句或疑問句中。Need she go there at o

6、nce ? Yes, she must. No, she needn't.(2) dare/dared 表示“敢”通常用于否定句、疑問句和條件從句中。Dare she go home alone at night? Yes, she dare. No, she daren't.注：need和dare也可用作行為動詞。后接動詞不定式。Does he need to clean the room now ? Does she dare (to) go home alone?How dared they say such a thing ?5.shall 和 should(1) sh

7、all 用于第二, 三人稱, 表示說話人的意愿，有 “命令”、“警告”、“威脅”、“強制”、“允諾”等意思。You shall do as 1 say.(強制)You shall not touch my things警告)All the students shall wait outside. You shall get a new bike if you do well in the exam.(2) 在疑問句中，shall用來征詢對方意見或請求指示，用于第一、三人稱。Where shall I wait for you?Shall he come at once?(3 ) should

8、作為情態(tài)動詞，表示 “應(yīng)該”。He should be here at any moment. You should keep your word(4) 表示驚奇作“竟然”解It is strange that he should come to school late.6will 和 wouldAwill(1) will 表示“意志”、 “意愿”，可用于各種人稱。If you will help me, I shall be grateful to you.(2) will 在疑問句中用于第二人稱時，表示詢問對方的意愿或向?qū)Ψ教岢稣埱?。Will you please give him a m

9、essage when you see him?(3) 表示習(xí)慣性動作，有 “總是”、 “慣于”的意思。Fish will die out of water.I push the door, but it won'topen.The girl will often spend the evening with her mother Bwould(1) would 是 will 的過去式，表示過去時間的 “意志”、 “愿望”,用于各種人稱。They said that they would help us(2) 表示說話人的意愿或向?qū)Ψ教岢稣埱?.Would you like/love

10、to see a film?Yes, I'd like/love to.No, I don'tthink I would.(3) 表示過去的習(xí)慣性動作。She would sit like that for hours.7. Ought to 表示義務(wù)，“應(yīng)該”、“應(yīng)當(dāng)”等否定式為 ought not to (oughtn'tto)，疑問式為 Ought I to? Ought he to go? Yes，he ought to8. used to do.過去常常 ”疑問式是 Used he to ?否定式是 used not to 或 use(d)n 't t

11、o 也可用 didn't use to.He used to get up very early in the morning.He used to get up very early in the morning, usen't he ?/ didn 't he ?There used to be a bus stop on that corner, usedn'tthere /didn'tthere ?A. 對現(xiàn)在情況的推測.1. must用在肯定句中，表示對當(dāng)前發(fā)生的事或情況做出很肯定”的推測，可譯作 準是”、一定是”、等。疑問和否定分別用 can

12、和can' t . can'常譯作 不可能”You must be very tired after the long walk.He has made great progress. He must be working very hard.There is no light in the room.She can'tbe at home.2. mightmaycould 用于肯定句，表示對當(dāng)前發(fā)生的事或情況做出 “不太肯定”的推測， “也許”、 “有可能”。He might/ may/ could be in the lab.也許他在實驗室里。She hasn

13、9;t come back；she mightmaycould be very busy today注意：* may not / might not 表示 可能不”He may not know the news now. They might not stay at home.B. 對過去情況的推測1. must have done 指過去 一定已做過 ”It must have rained last night , didn 'tit ?They must have lived here for 10 years, haven'tthey ?2. can ' t

14、/ couldn ' t have指過去不可能做過 ”The workers can 't have finished their work yesterday.3. * can / could have done在疑問句中表示對過去發(fā)生的事情的懷疑或不肯定. 可能”Can the workers have finished their work yesterday?4. may /might have done 用在肯定句中，表示過去"可能.” Tom hasn't arrived yet. He may / might have missed the tr

15、ain.5. *might/could have done 在肯定句中表示"過去本來能做 ，而實際上卻沒有做.”You might have been more careful.He could have passed the exam， but he didn't study hard.這里的may與might, can '與couldn'在時間上無甚差別，只是后者在語氣上比前者婉轉(zhuǎn)， 但需注意下面句中的用法。He said that she might have missed the train.（主句中，動詞 said是過去時，從句中只能用might。）He thought that she couldn 't have missed it .（主句中，動詞thought是過去時，從句中只能用 couldn't。）6.ought to / should have done 表"過去應(yīng)該做某事而實際上沒有做到，含有責(zé)備的意思.You should