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1、情态动词,特殊用法,表示客观可能性Accidents can happen on such rainy days.表示猜测（惊讶、怀疑、不相信的态度）Can this green bike be Liu Dongs?构成下列特殊句式：（）can not/can never too 或 cannot enough无论怎么也不过分；越越好；非常。One cannot be too careful.越认真越好。I cannot thank you enough.我对你感激不尽。You cant praise him too highly.你怎么表扬他也不过.(他十分出色)（2）cannot help
2、 doing/cannot help but do/cannnot but do”禁不住；不由得；不得不“。I cannot help admiring the picture whenever I look at it.When a close friend dies,you cannot but feel sad,Can(could)和be able to,都可以表示能力,意思上没有区别.但can 只有现在式和过去式,而be able to 则有更多的形式.例如:No one is able to do it.没人能做这件事.Will you be able to come tonight
3、?你今晚能来吗?Im sorry I havent been able to answer your letter.对不起我一直没能给你回信.She said she had not been able to come earlier.她说她没有能够来得更早一些.但是,在表示成功地完成某一具体动作时,通常不用could,而用was/were able to 来表示.这时,was/were able to 相当于managed to 或succeeded in doing,表示经过一番努力，终于能够。They were able to put out the fire without any h
4、elp from the firefighters.,must有“偏要、硬要”之意。Hey,beys Must you shout so loudly?How old are you,madam?If you must know,Im twice my sons age.表示推测+be done+be doingmust+have done+have been done+have been doing否定式 must not(mustnt)表示“禁止”；You mustnt touch the fire.Must we finish the work tomorrow?No,you needn
5、t(dont have to),but you must finish it in three days.,may句式用来表示祝愿。May you succeed!=I hope you may succeed.May you be happy,healthy and wealthy!may(might)as well动词原形：不妨做If that is the case,we may as well try.Now that they were all here,she might as well speak her mind.,1.b.shall 用于第二，第三人称，表示说话人给对方的命令
6、(法律法规的规定），警告，允诺或威胁。在疑问句中，表示征询听话人是否愿意。You shall have my answer tomorrow.(允许)He shall be sorry for it one day,I tell you.(警告)You shall do as I tell you.(命令或分咐)Shall you go with me?(征询意见)2.用于一、三人称的疑问句中，表示说话人征求对方的意见和向对方请示。例如:Shall we begin our class?When shall my father be able to leave hospital?,“The i
7、nterest _ be divided into five parts,according to the agreement made by both sides,”declared(宣布)the judge.A.may B.should C.must D.shallIt has been announced that candidates _ remain in their seats until all the papers have been collected.A.can B.will C.may D.shall,should表示预测可能性，并译作“可能，(按道理)应该”；It is
8、 ten oclock.They should come here now.(按道理应该到了)表示说话人对已经出现的事态感到“惊奇、惊喜、怀疑”“竟然”Im amazed that Mr.Harris should have said nothing about the matter.Why/How should结构表示说话人对某事不能理解，感到意外、惊异等意思，意为“竟会”。Why should you be so late?你今天来得怎么这么晚？How should I know?我怎会知道！(意为：我不知道。),will用于各种人称，表示意志或决心。will指现在，would则指过去。I
9、 will do my best to help you.我会尽力帮你的。He said that they would help us.他说他们会帮助我们的。I have told him again and again to stop smoking,but he will not listen.表示习惯性、经常性、倾向性，意为“总是”，“惯于”或“会要”。will指现在，would是指过去。鱼没水就会死。Fish will die without water.星期天当他在北京的时候就会来看我。He would come to see me on Sunday when he was in
10、 Beijing.,would 与used to 的区别：We would sit in the yard every evening and listen to his story.(过去常有的习惯，但言下之意是现在可能还有这样的习惯。)We used to sit in the yard every evening and listen to his story.(过去常有的习惯，但言下之意是现在没有这样的习惯了。)There used to be a park here.,used to表示过去的某种习惯，现在已经没那样的习惯了；would 表示过去有某种习惯，现在可能还有。表示过去的状
11、态，只能用used to，不能用would。,need既可以用need to be done 也可以使用need doing，两种形式都表达被动的意义The house needs painting=the house needs to be painted.The watch needed repairing=the watch needed to be repaired.,表示请求或允诺的情态动词(1)向对方提出建议时用：Shall/May/Might/Can/Could I/we.?Shall he/she/they.?Would/Will you.?(2)could/might/wou
12、ld/should表示委婉的语气,肯定回答：用may/can;不用could/might否定回答：用cant/mustnt。Could/May I use your bicycle tomorrow morning?Yes,you can/may.Shall he come to see you?Of course,please.And Id rather he told me the truth.,must表示有把握的推测，意为“一定，肯定”，用于肯定句中。否定句，疑问句用cantmay,might表示“或许，大概”。用于肯定句或否定句中，用might 比 may语气更加不肯定。should表示按常规、常理推测，意为“可能”或“应该”。will,would意为“大概，也许”。would 的肯定性不如will强，语气比较弱。,
