1、Grammar 情態(tài)動(dòng)詞的用法,Unit1 Festivals around the world,情態(tài)動(dòng)詞的語(yǔ)法特征,1) 情態(tài)動(dòng)詞不能單獨(dú)做謂語(yǔ), 除ought和have外, 后面只能接不帶to的不定式。,2) 情態(tài)動(dòng)詞沒(méi)有人稱(chēng), 數(shù)的變化, 但有些情態(tài)動(dòng)詞, 如can、will也有一般式和過(guò)去式的變化。,3)情態(tài)動(dòng)詞的“時(shí)態(tài)”形式并不是時(shí)間區(qū)別的主要標(biāo)志, 不少情況下, 情態(tài)動(dòng)詞的現(xiàn)在式形式和過(guò)去式形式都可用來(lái)表示現(xiàn)在時(shí)間、過(guò)去時(shí)間和將來(lái)時(shí)間。,只作情態(tài)動(dòng)詞的 can / could, may / might, ought to, must 可情態(tài)可實(shí)義的 need, dare 可情態(tài)可助

2、動(dòng)詞的 shall / should, will / would 相當(dāng)于情態(tài)動(dòng)詞的 have to, used to,1) can的主要用法是： A. 表示體力或腦力的能力： eg. The girl can dance very well. B. 表示說(shuō)話的推測(cè)事物的可能性等: eg. Can the news be true? C. 在口語(yǔ)中, can可以表示請(qǐng)求或允許: eg. Can I sit here?,can 和could：,can表示“能夠”時(shí)與短語(yǔ)be able to同義，但can只用于一般現(xiàn)在時(shí)或過(guò)去時(shí)，而后者可用于各種時(shí)態(tài)。另外，can表示個(gè)人有某種能力，而be able

3、 to表示某人通過(guò)努力、克服困難做成某事，相當(dāng)于succeed in doing sth.；敘述過(guò)去事實(shí)時(shí)，最好用was / were able to，因?yàn)閏ould只表示過(guò)去具有某種能力。,如： Can you understand the different kinds of English these people are using? Two years later, he was able to speak very good Chinese.,2) could的主要用法是： A. could 是can的過(guò)去式, 表示與過(guò)去 有關(guān)的能力和推測(cè): e.g. We all knew th

4、at the young man couldnt be a doctor. B. could可以代替can表示請(qǐng)求, 但語(yǔ)氣較can客氣、委婉:,e.g. Could you lend me your dictionary? Could I use your bike? 3) can和could接動(dòng)詞的完成形式，表示可能已經(jīng)做某事。can用在否定和疑問(wèn)句中, 表示不相信、懷疑等態(tài)度。 e.g. They cant have gone out because the light is still on.,以could或would提問(wèn)時(shí)，不能再以could或would作答，而應(yīng)該用can或will

5、。如： Could I borrow your dictionary? Yes, of course you can.,may 和might ： may 常用來(lái)表示： A. 表示請(qǐng)求、允許; 比can較為正式: e.g. May I come in ? You may go now. B. 表示說(shuō)話人的猜測(cè): “也許” “可能”: 通常只用于肯定句和否定句中。,e.g. -I believe the man is from England. -But I may be wrong. The guest may arrive this afternoon. 在肯定句中，may的可能性比can 高

6、，may表示現(xiàn)實(shí)的可能性，can表示理論上的可能性。如：,The road may be blocked. 這條路可能不通了。 The road can be blocked. 這條路可能會(huì)是不通的。 在疑問(wèn)句中，表示可能性用can。 如：Where can he be? 他會(huì)在哪呢？,C. 表示祝愿;但語(yǔ)氣較正式: e.g. May you succeed! May you have a good journey! might 的用法有: 多在間接引語(yǔ)中表示過(guò)去的可能和允許。如: She said that he might take her bike. 她說(shuō)他可以拿她的自行車(chē)去用。,除了在

7、間接引語(yǔ)中以外，might 一般不表示過(guò)去的可能或者許可。如要表示過(guò)去的可能可以用could, 表示過(guò)去的許可可以用was (were) allowed to 或者h(yuǎn)ad permission to 。 表示現(xiàn)在的可能，其可能性要比may 小。如：,She might go home tomorrow. 說(shuō)不定他明天會(huì)回家。 表示現(xiàn)在的許可, 語(yǔ)氣比may較委婉, 一般用于疑問(wèn)句(包括間接疑問(wèn)句), 不可用于肯定句或者否定句。 如: Might I have a word with you? 我可以和你說(shuō)句話嗎？,will和would：,1. will是助動(dòng)詞或是情態(tài)動(dòng)詞？ will用于構(gòu)成將

8、來(lái)時(shí)是助動(dòng)詞。用于表示“意志”“決心”“請(qǐng)求”是情態(tài)動(dòng)詞。would亦同理。 e.g. I will tell you something important. 我要告訴你一些重要的事。 （助動(dòng)詞）,Will you tell her that Im here? 請(qǐng)您告訴她說(shuō)我在這兒，好嗎？ （情態(tài)動(dòng)詞） 2. 在疑問(wèn)句中用于第二人稱(chēng)，提出請(qǐng)求或詢問(wèn)。 e.g.: If you want help - let me know, will you? 如果你需要幫助, 讓我知道, 好嗎?,Will you type this, please? 請(qǐng)打印這個(gè), 好嗎？ Wont you sit dow

9、n? 請(qǐng)坐下, 好嗎？ 3. would比will客氣委婉。 e.g.: Would you help us, please? 請(qǐng)您幫助我們，好嗎？,（表請(qǐng)求）,Id go there with you. 我要和你一塊到那兒去。 Teacher wouldnt allow it. 老師不會(huì)允許這件事。,（表意愿）,（表許可）,shall和should：,1. shall用于構(gòu)成將來(lái)時(shí)是助動(dòng)詞。 shall用于征求對(duì)方的意見(jiàn)，表示 “決心” 是情態(tài)動(dòng)詞。 e.g.: Perhaps I shall pay a visit to England this winter. 可能今年冬天我會(huì)去英國(guó)觀光

10、。 （構(gòu)成一般將來(lái)時(shí), 助動(dòng)詞）,Shall we go by train, Mom? 媽媽?zhuān)覀兂嘶疖?chē)去好嗎？ （用于征求對(duì)方的意見(jiàn)，情態(tài)動(dòng)詞） I shall go at once. 我必須立即去。 （表 “決心”，情態(tài)動(dòng)詞）,shall可以用于第一、三人稱(chēng)的疑問(wèn)句，表示征求意見(jiàn)或許可；還可用于第二、三人稱(chēng)的陳述句中，表示允諾、警告、命令或威脅等。如： You shall be punished if you break the rule.,2. should表示義務(wù)、建議、勸告，意為“應(yīng)該”?！皊hould+ have+過(guò)去分詞”表示本應(yīng)該在過(guò)去做但沒(méi)有做。 eg: You should

11、 keep your promise. 你應(yīng)該遵守諾言。 She should have passed the exam. 她應(yīng)該通過(guò)考試的。,must和 haveto,1.must用于一般問(wèn)句中,肯定回答用must否定式用neednt或dont have to，做“不必”, mustnt表示“禁止，不允許”, MustIfinishallassignmentsatatime?,Yes, you must. No,youneednt.,I dont like this TV set. We must buy a new one. There was no more bus. They had

12、to walk home.,2.表示“必須”這個(gè)意思時(shí)，must和haveto稍有區(qū)別。must著重說(shuō)明主觀看法，haveto強(qiáng)調(diào)客觀需要。另外，haveto能用于更多時(shí)態(tài)。,Youmustbethenewteacher. Hemustbejoking. Thereisnobodyhere.Theymusthaveall gonehome.,3.must表示對(duì)某人某事的猜測(cè), 作“準(zhǔn)是”, “一定” , 一般用于肯定句中。對(duì)過(guò)去發(fā)生的事情作肯定判斷用must have done,He must come and worry her with question, just when she wa

13、s busy cooking the dinner. Of course，after I gave her my advice，she must go and do the opposite.,4. must表示“偏要, 硬要”, 指做令人不快的事情,can / could, may / might, should和must都可表示肯定的推測(cè)。can / could表示客觀可能性；may表示推測(cè)時(shí)，其語(yǔ)氣不肯定；might語(yǔ)氣更弱，表示某事實(shí)際發(fā)生的可能性；should表示確定或可能有的未來(lái)或期待；must表示比較肯定的語(yǔ)氣。如：,I think advertisements can be q

14、uite dangerous. The newcomer may be dismissed by the company. The rescue team should arrive by 5 oclock this afternoon. I think the old woman must be a nice person.,could, might, would, should都可表示委婉語(yǔ)氣。如: I wonder if you could let me use your cell phone. Might I know your telephone number?,2. A: _ Xi

15、ao Feng find the origin of Easter from that book? B: No, he _.,1. A: _ you like to go to a special event with us on Saturday? B: Yes, I _ _.,Would,d like to go with you on,Saturday,Could,couldnt find it,Exercise,3. A: _ I go with my friend to the harvest festival? B: Yes, you _ _.,4. A: If I want to

16、 be a doctor _ I study science? B: Yes, you _.,should study science,May,may go (with your,should,friends),5. A: He is very handsome. _ he play the role of the prince? B: No, he _ _.,cant play the role of the,Can,prince,6. A: The neighbour s children are older this year. _ they stop playing tricks at

17、 Halloween? B: Perhaps, they _ _. _ _.,Might,or Should,might stop,or should stop playing tricks,playing tricks at Halloween,at Halloween,can; could When I was young I _ climb any tree in the forest. Learning a language _ be a real challenge.,could,can,II. 選用正確的情態(tài)動(dòng)詞填空。,may; might I asked if I _ go home half an hour earlier today. There _ not be enough money to pay for the repairs.,might,may / might,will; would When he got older, he _ never do his homework. Nancy _ keep talk