1、be able to可用于各种时态（二者不连用），was were able to do sth:过去某一场合设法做成了某事（=managed to do sth.）（2）“有时候可能会”:Anyone can make mistakes.（3）表示“许可“：Could Can I go now ? Yes ,you can. No, Im afraid.在这种语境中could更委婉客气；二者无时间差别； could 只用于疑问句中，不用于肯定句中，回答时用can.（4）表示推测或惊异（主要用于否定句、疑问句或感叹句） This cant be done by him. Can this be
2、 true? How can you be so careless！can 表示推测时只用于否定句和疑问句，对过去的猜测后+have done, couldnt 可能性比cant 小couldnt have done 可表示过去有能力做某事，但没有做。2.may , might 的用法（1）表示可能性：might 可表示过去的可能性，也可表示现在或将来的可能性，比 may可能性小.may 不用疑问句首表可能性，此时用“can”eg : Can the story be true?might have done 可表示过去可能会发生而实际上未发生地事情That was too dangerous
3、, you might have killed yourself.may might have done :对过去所发生的事情的推测。may be （做谓语）/ maybe （adv.）（2）表示“许可”意为“可以”；在疑问句中“might”语气更委婉客气 You may go now./ May/Might I go now?（3）may +主语+ 动词原形表祝愿 May all your dreams come true ！May you be happy ！（4） may might as well + 动词原形：还是做什么为好 eg: You may might as well do
4、it at once . 3must & have to 用法（1）must （肯定推测） must do sth must be doing sth must have done sth（2） must 表示“必须“，多强调主观看法（客观需要时，常用have to ）（3） must 否定式为must not 或 mustnt，表示绝对禁止回答由must 引起的问句时，否定回答不用mustnt,而要用neednt 或dont have to ,肯定回答可用must（4）must 可表示“偏偏“，指令人不愉快的事情 Why must it rain on Sunday?（5） must 可表示
5、必然的结果 All men must die.（6）have to “必须”由于客观的外界状况而“必须”，否定式dont have to He had to sell his house to pay off his debt.4. need 的用法（名词/ 情态动词/及物动词）（1）回答用need提问的问句时，肯定回答用“must（口语中也可用have to 或have got to ）;否定回答时要用neednt 或dont have to Need I go at once? Yes, you must. No, you neednt. （2） need 用作名词时，可构成句型：ther
6、e is （no） need （for sb） to do sth.（没）有必要做某事。neednt 表示主观上的没有必要；dont have to 表示客观上没有必要。neednt have done 表示过去不必做某事，但实际上做了 didnt need to do 表示过去不必做且实际上也没做You neednt go to work today and just take a rest. You dont have to walk so fast and there is still enough time left. She need not have come yesterday.
7、 She didnt need to come yesterday.need to be done =need doing Want , require 作需要讲时，与need 用法相同5.dare 的用法dare: 情态动词+ 动原； 用于否定、疑问句和条件从句。 无人称（数），有过去式dared 实义动词：dare （not） to do sth She darent doesnt dare to say anything about it. dared not didnt dare to I dare say 固定短语；表示“我认为；我相信”I dare say he is right.
8、6.will 的用法（1）表意愿、意图和决心；意为“要，愿”。用于各种人称 eg : Will we buy a car? （要） I wont do so .（愿） Will 表将来时不可用于条件状语从句中，但若will 为情态动表意愿则可以。（2）表示功能，意愿“能，行” This will do if there is nothing better. （3）与第二人称连用，用于疑问句，表示“邀请，请求。”Will you give me a piece of paper?（4）表示推测、估计，意为“可能，想必，大概” That will be the postman ringing.（5
9、）will 表示经常性，习惯性，倾向性，意为“经常、惯于、总是” Oil will float on water.（6） 用于祈使句的附加疑问句 Come here early tomorrow, will you ? let us开头的句子的附加疑问句用will you ，表示后面的动作不包括主语you 7.would 的用法（1）用于过去时中，表示主观愿望或意志，意为“愿意” I told him that I would go along with him .（2 ） 用于第二人称表示谦恭的请求或征求意见 ，比will 更客气。（3）表推测，意为“大概，也许”可指现在或过去（will表推
10、测指现在或将来） This would will be the book you are looking for. That would be in the spring of 1997。（不用will）（4）表示过去的习惯，后接动词原形，意为“总是，总会”The old man would sit near the fire for hours on winter evenings.（5） would like sth to do sth. would rather + 动原从句（用虚拟语气） eg : I would rather stay here. would的固定句型 I d rat
11、her you came tomorrow.I would rather（that） he had left last week. would prefer “宁可，更喜欢” ,would 可以省略prefer to do sth. doing sth.（更愿意做sth） prefer A to B 喜欢A胜过B prefer A rather than B:宁愿A也不愿B prefer sb. to do sth.:宁愿某人做某事 He preferred doing sth to doing nothing. He would prefer to walk there rather tha
12、n go by bus.8.shall 的用法（1）用于一、三人称的疑问句中表示征求对方的意见或向对方请示 Shall she go now?（2）用于二、三人称的陈述句，表示说话人给对方的命令、警告、允诺或威胁。 You shall be punished if you do it again.（3）用于第一人称表示决心。 We shall catch up with them.（4）用于第三人称，在条约、规定、法令等文件中表示义务或规定中“应必须” The National Party Congress shall be held every 5 years.9should d的用法（1）
13、作为shall 的过去式，用于第一三人称，多用在间接引语中，以征求对方的意见。 Mr. Lin asked if he should get his visa the next day.（2）表示责任、义务，意为“应当、应该” We should respect our teachers and parents.（3）表示有一定根据的推测，意为“可能、该”（肯定语气没有must强）He should be sixty years old. He should have got there by now.（4）表示惊讶、难以置信或不应该发生地事，意为“竟然” The gentleman shou
14、ld be rude to a lady.（5） should have + 过去分词，表示本应该做到而实际上没有做到10Ought to 的用法Ought to 同should 意为“应该、应当”表示责任、义务、劝告、可能性，语气上比should 强， 无人称和数的变化，否定形式为ought not to 或oughtnt to ;一般疑问句将ought 置于主语前。辨析：ought to &should二者在表示责任、义务时差别细微should多表达自己的主观看法；ought to 则多反映客观情况，在谈判法律、义务和规定或要使自己的意见听起来像义务和法律一样有力使用。11had bett
15、er 的用法主要用来表示劝告或建议，其后跟动词原形；否定形式为had better not.（1） you might/ l suggest / I wish you 都可用来表示建议且比had better 客气（2）may might as well + v动原意为还是。的好，也可表示建议。12、used to 的用法（1）used to + v 原形，表示“过去常常”，没有人称和数的变化；仅用于过去时，“今非昔比” There used to be a temple here.（2）在疑问句、否定句、否定疑问句或强调句中， 可有两种形式疑问句：Did you use to Used yo
16、u to /go to the same school as your brother ?否定句：I usednt to go there=I didnt use to go there. 否定疑问句：Usednt you to be interested in the theater? =Didnt you use to be interested in the theater?强调句： I certainly used to smoke.I certainly did use to smoke.反问疑问句和简略答语中 She used to be very fat, didnt she ?
17、 usednt she ?used to do sth & be used to do sth & get /be /become used to（doing ）sth. used to do & would do（1）used to do 强调过去行为与现在的对比，would 仅表示过去习惯性或重复性的动作。（2）used to 不能与表示确定时间段连用。 He used to work here for 20 years. （）（ 3 ） used to 可用于无人称和存在句，而would不可。 eg: There used to be a big tree. It used to be
18、said that （过去人们常说）13.情态动词+have done 的用法（1）cancould + have done 用于疑问句或否定句中时，表示对过去情况的猜测，could have done 也可用于肯定句表好似“可能已经”。或“本来可以（可能）” You could have done better, but you didnt try your best . I saw Mr. Zhang just now and he couldnt have gone to Beijing.（2）must have done 只用于肯定句；对过去情况的肯定推测，意为“想必，准是，一定” I
19、 must have rained last night , for the road is muddy.对过去情况的否定推测要用cant couldnt have done,不用mustnt.（3） may might have done 一般只用于肯定句和否定句，不用于疑问句，表示对过去情况不肯定的推测，意为“也许已经。”might have done ,还可用来表示“本来可能发生而实际上未发生” Its too late . I think he may have gone to bed.（4） need have done 通常用于否定句和疑问句中，表示不必做的事情却做了。 You n
20、eednt have told her the news , for I had told her.（5）should ought to have done 本应该做sth 而没有做 You should have told her the news.（6） would rather have done :当时宁愿做了某事，否定式为 would rather not hve done I would rather have refused his offer.（7） had better have done sth: 用于事后的建议，含有轻微的责备口吻，意为“当时最好做了某事”否定形式为had
21、 better not have done sth. Youd better have started earlier. 14.表推测的情态动词的反意疑问句Must , may, can, 等表示推测的情态动词，其反意疑问句的变化过程为：把原句还原为不表示推测的句子。根据还原后的句子变反意疑问句。She must have seen the film.-She has seen the film ,-hasnt she ? She must have seen the film last night.She saw the film last night. - didnt she ?人生格言！1.当别人停滞不前时，你不可以放纵自己，你要继续拼搏，因为只要你的付出比别人多一点点有一天你就会丰收。2.每次比上一次好一点点，那么成功就会越来越近。3.真正的自信就是看到自己的强项或者说好的一面来加以肯定、展示或表达。4.为什么要绝望？想想自己是多么独一无二！ 若哥 2009 10.6 12：29（完）
