be动词、助动词、情态动词用法课件(PPT35张).ppt

Be动词,一般现在时中be动词的用法 be am is are（1）am用在I后 I am a student.Im happy.（2）are用于复数主语和第二人称单数（你，您）等情况 Are you Chinese?They are basketball players.The books are expensive.,（3）is用在主语是第三人称单数或不可数名词等情况 He is my friend.The dog is yellow.Time is money.be动词的缩写形式 I am=Im he/she/it is=hes/shes/its we/you/they are=were/youre/theyre is not=isnt are not=arent who is=whos what is=whats,be动词的在一般现在时中的各种句型 1）肯定句：主语+be+其他成分 She is beautiful.2）否定句：主语+be+not+其他成分 She is not beautiful.3）一般疑问句（用yes或no来回答）：be+主语+其他成分+？Is she beautiful？4）特殊疑问句：疑问词+be+主语（其他成分）+？Whats your name?Whos that?,be的用法口诀：我用am，你用are,is跟着他、她、它。单数is，复数are，勿忘be的三变化。变疑问，往前提，句末问号莫丢弃。变否定，更容易，be后not莫忘记。疑问否定任你变，句首大写莫迟疑。一般现在时中be动词的用法相对简单，上面的口诀基本包括了be动词的各种问题。,Exercises,用am/is/are填空1、She（）a student.2、His jacket（）on the table.3、We（）family.4、-How（）you?-I（）fine,thanks.5、Jack and I（）good friends.6、（）she a student?7、（）you a teacher?,助动词do/does,什么是助动词？顾名思义，助动词就是帮助动词的，而本身没有实际意义的动词，是具有雷锋精神的词汇。助动词do的三种变化形式 do 第三人称单数时使用的does 过去式did,do的基本用法：1 构成否定句 2 构成一般疑问句及回答 3 构成特殊疑问句do的各种形式 肯定式：do 否定式：dont/do notdo用在第一人称单复数、第二人称单复数和第三人称复数作主语，且时态为一般现在时的句子，如：I like that dress.否定句：I dont like that dress.一般疑问句及回答：-Do you like that dress?-Yes,I do/No,I dont.,特殊疑问句：Which dress do you like?does 肯定式：does 否定式：doesntdoes用在第三人称单数作主语，且时态为一般现在时的句子当does出现时，句子中用动词原形。如：She likes that dress.否定句：She doesnt like that dress.一般疑问句及回答：-Does she like that dress?-Yes,she does./No,she doesnt.特殊疑问句：Which dress does she like?,Exercises,按要求改写句子：1.Ithinkheisveryold.(否定句)I_thinkhe_veryold.2.Thissignmeans“Nosmoking”.（改为特殊疑问句）What_thissign_?3.Myplanthastwogreenleaves.(就划线部分提问)_ _ _ _ _ _plant _?4.I love my parents.（改为一般疑问句）_?,翻译句子 1 他不喜欢花。2 他每天做什么？3 How do you go to school?4 Which film do you like best?,情态动词,情态动词有一定的意义 无人称和数的变化 除了ought和have通常不带to，后加动词原形 表示说话人的语气或情绪（请求、警告、命令等）,特点：,情态动词,need,will/would,can/could,have/had to,may/might,used to,ought to,dare,shall/should,must,1.can/could 1)表示能力 I can speak English and French.He can do it himself.2)表示事物一时的特征，理论上的可能性 Its always warm here,however,sometimes it can be very cold.Even an experienced teacher can make mistakes.3)表示允诺，许可-Can I eat some candies,mom?-Yes,you can./No,you cant.You can have my seat.I am going now.,4)表示推测-Someone is knocking at the door.Who can it be?Can it be Tony?-No,it cant be him.He is in Beijing now.No,he couldnt be a thief.Could是can的过去式，用法与can类似，常用于过去时中；could 用在现在时中表示表示委婉、客气，相当于can。-Could you help me?/Could you do me a favor?-Sure./Certainly.,2.may和might 1)表示请求或许可-May/Might I come in?-Yes,you may.2)表示可能性的推测 She has changed so much that you may well not recognize her.Its too late.I think he may/might have gone to bed.3)may用于祈使句表示祝愿 May you succeed!May you return in safe!关于may的一般问句的回答：肯定回答为“Yes,please./Certainly./Sure.”否定回答为“Please dont./No,you cant/musnt.”,might是may的过去式，用法与may类似，常用于过去时中；用在疑问句中，还可表示委婉客气。,3.must 1)必须 Must I say sorry?Yes,you must./No,you neednt./No,you dont have to.You must see a doctor.2)猜测，“肯定，准是”She must be doing her homework now.There must be something wrong with my computer.It must have rained last night.The ground is wet.,3)偏要，硬要 If you must smoke,please go out.4)否定，表示“禁止”You mustnt play with fire.You may hurt yourself.must一般疑问句的否定回答用neednt或dont have to,而不用 mustnt.因为mustnt表示“不可能，禁止”，语气比较强硬,提到must,就不得不讲到它和have to的对比。1)二者都有“必须”的意思，have to表示客观上的需要，有被迫的意为，表示“不得不.”；must表示说话人主观上的看法，即主观上的必要。ex:My brother is ill,so I have to call the doctor in the middle of the night.I must work hard for my future.2)have to有人称、时态和单复数上的变化，而must只有一种形式。have to had to I have to/she has to ex:He had to look after his sister,because his parents were not at home yesterday.3)在否定形式中，“dont have to”表示“不必”,“musnt”表示“禁止”ex:You dont have to tell him this news.你不必告诉他这个消息。You musnt tell him this news.你一定不要告诉他这个消息。,4.shall的用法 1)shall常用于第一人称，表示简单的将来，构成将来时态。(助词)ex:I shall think it over and let you know my idea.When shall we meet again?We shall have a good time in the park.2)shall用于第一人称，还可以表示征求对方的意愿。ex:What shall we do this evening?Shall we go to the movies?3)shall用于第一、第三人称疑问句中，表示说话人征求对方的意见或向对方请示。ex:Shall we begin our lesson?（征求意见）When shall he be able to leave the hospital?（请示）4)shall用于第二、第三人称，表示说话人给对方命令、警告、允诺或威胁。,ex:You shall fail if you dont work harder.(警告)He shall have the book when I finish reading.(允诺)You shall get a bike as your birthday.(允诺)He shall be punished.(威胁)shall实际上是一个情态助词，表示“将要、要不要、应该”等意义，语气比较委婉，用于疑问句时意思为“干.好吗？”“要不要.”,shall和will的对比 1）shall和will作为助动词可以与动词原形一起构成将来时。如：I shall study harder at English.我将更加努力学习英语。He will go to Shanghai.他要去上海。2）以前的语法中，shall用于第一人称，will只用于第二、第三人称。现在，尤其是在口语中，will常用于第一人称，但shall只用于第一人称，如果用于第二、第三人称，就不再有“将要”的意义，就变成命令、警告或威胁的意思了。He shall come.(他必须来。)He will come.(他要来。),5.should的用法 1）表示义务或责任 You should work hard and take care of your family.Visitors shoud obey the rules of the zoo.2）表示劝告或推荐 He should stop smoking.You shouldnt leave the baby alone in the house.They should have called the police.3）表示假设的结果(可简略)We should move to a large house if we had money.4）用在形容词anxious,sorry,concerned,happy,delighted等后接的从句中(可简略)We are sorry that you should feel uncomfortable.,5）用于if和in case引导的从句表示不太可能的事 If you should change your mind,do let me know.Should anyone telephone,tell them Im busy.6）用于so that和in order that之后表示目的或动机 He put the cases in the car so that he should be able to make an early start.He repeated the instructions slowly in order that he should understand.7）用于表示请求的客气说法 I should like to make a phone call,if possible.We should be grateful for your help.8）用于表达不成熟的意见 I should say shes over forty.I should imagine it will take about 3hours.,9）与疑问词连用表示不感兴趣，难以置信等 How should I know?Why should he think that?,6 ought to的用法,1、ought to比should语气强烈，一般用于肯定句和否定句。1)（表示责任、义务等）应当、应该 You ought to work harder than that.2)（表示劝告、建议等）应该，该 You dont look well.You ought to go to see the doctor.3)（表示猜测、期望等）总应该，理应 It ought to be a fine day tomorrow morning.4)ought to+have+过去分词，表示过去应该做某事但实际上没做 You ought to have told me that news.(but you didnt)这时ought to可以和should互换，should也有此用法,2、ought to的否定式和疑问式,ought to的否定形式是在ought后直接加not ought not to，可以缩写为oughtnt.ex:One ought not(oughtnt)to cross the street against the red light.ought to的疑问式是将ought提到句首构成 ex:-Ought we to do it at once?-Yes,you ought to.在反意疑问句里，下面两种形式都可以：He ought to be here now,shouldnt(oughtnt)he?,7、need的用法,1)need作情态动词时，后加动词原形，无人称和数的变化，多用于否定句和疑问句中。ex:You neednt worry.2)由need引出的一般疑问句，肯定回答常用must或have to；否定回答用neednt.ex:-Need I answer the question?-Yes,you must./Yes,you have to.-No,you neednt.3)用在if/whether之后4)或与hardly,never,no one,nobody连用 ex:I need hardly tell you that the work is dangerous.,5）need还有实义动词的用法，意思是“需要”，否定形式为dont need ex:I need you.我需要你 I dont need your help.我不需要你的帮助。sb.need doing sth.=sth.need to be done.need doing sth.需要做某事（有被动的意思）need to do sth.需要做某事 ex:My clothes need washing.=My clothes need to be washed I need to wash my clothes.,8、dare的用法,1）dare用作情态动词时，意为“敢”，后接动词原形，通常只用于否定句或疑问句以及if或whether之后,一般不用于肯定句,其否定形式常缩写为darent ex:She darent come to see you.Dare you say that to the boss?I dont know whether he dare try.2)作实义动词时，意为“敢于”，有各种词形变化，可用于各类句子（肯定句、否定句、疑问句等）ex:Do you dare to tell him?Do you dare to answer me if I call you?He doesnt dare to interrupt.他不敢插嘴。,9、used to do sth.过去常常做某事（现在已经不做了）,EX:I used to go to the cinema a lot.He used to be a heavy smoker,didnt he?He used to be a heavy smoker,usednt he?补充：1）be used to doing sth/be used to sth(to是介词)习惯于做某事 ex：She isnt used to living in the countryside.Are you used to the food here?2）be used to do sth 被用来做某事 ex：Computers are used to do many things for people now.,10、will的用法,作情态动词：1）（表示意愿、意志）愿、要 ex:You will come,wont you?你会来的，是不是？I will do my best to help you.2）（表示经常性、习惯性、不可避免性）经常，惯于，总是 ex：These things will happen.People will talk.人总会说闲话。Water will boil at 100.3）表示说话人向对方提出请求或询问对方的意见，意思为“你.好吗、你愿.吗”,ex：Will you join us?你愿意加入我们吗？Wont you sit down?你不坐下吗？4）表示说话人的猜测，意为“大概”ex:That will be the book you want.那大概是你要的书。Ask him,he will know.问他吧，他应该知道。5）表命令或指示 ex：No one will leave the examination room before 12 oclock.任何人不得在12点之前离开考场。6）表示许诺、指示、叮嘱等 ex:You will have your share.你会得到你的那一份。7）表执意 ex:He will do these things!他总是爱干这样的事！,would的用法,would与will的用法类似，是will的过去式，但在表示征求意见或提出请求时，will和would都可用，would此时不表示过去，而是表示委婉的语气（此时主要用于第二人称的疑问句中）ex:Wont you take off your coat?你要不要把大衣脱掉？Will/Would you please post the letter for me?请帮我寄了这封信好吗？注意：1）有时为使语气委婉，可用否定式。总的说来，would比will委婉些，用wont和wouldnt比单独用will和would要委婉。ex:I wont go out today.I wouldnt to go out today.2）would有时用于提出想法，通常与like,love,hate,prefer,be glad,be happy等连用，若用于第一人称也可将would换成should,ex:Id like/love to have a look at it.I would prefer not to go out today.,