情態(tài)動詞公開課Grammar (2)課件

1、Grammar 情態(tài)動詞的用法(I) Unit1 Festivals around the World情態(tài)動詞的語法特征1) 情態(tài)動詞不能單獨做謂語; 除ought和have外, 后面只能接不帶 to的不定式。 2) 情態(tài)動詞沒有人稱, 數(shù)的變化, 但有些情態(tài)動詞, 如can、will也 有一般式和過去式的變化。3)情態(tài)動詞的“時態(tài)”形式并不是時間區(qū)別的主要標(biāo)志, 不少 情況下, 情態(tài)動詞的現(xiàn)在式形式和過去式形式都可用來表示 現(xiàn)在時間、過去時間和將來時間。只作情態(tài)動詞的 can, could, may, might, ought to, must可情態(tài)可實義的 need, dare 可情態(tài)可助

2、動詞的 shall, should, will, would相當(dāng)于情態(tài)動詞的 have to, used tocan和could1. 表示能力，意為“能，會”，could是過去式。 I can speak English fluently while he cant. I couldnt get tickets; they were sold out.2. 表示請求或允許，could表示更委婉的語氣，但回答時只 能用can。 You can use my dictionary. Could I use your computer? Yes, you can.can和could3. 表示說話者主

3、觀猜測，一般用于疑問句和否定句， 此時could不是過去式，它的可能性比can小。 Look! Someone is coming! Who can it be? It cant be him. He has gone to Paris. If youre not careful, you could get into even worse trouble.4. 用于肯定的陳述句中，表示理論上或習(xí)慣上的可能性。 Accident can happen to any drunken driver. Even the top students can make mistakes in the ex

4、am.注意：can和be able to3. 在否定結(jié)構(gòu)中，was/were able to與could沒有區(qū)別。She ran fast but she couldnt/ wasnt able to catch the bus.may和might1. 表示允許，許可。might在語氣上比may更委婉。以may/might開頭的問句在肯定回答時用may/can;否定回答中要用mustnt/cant。You may keep the book for two weeks.May I use your telephone? Yes, you may/can. (No, you mustnt/can

5、t.)will和would1. 表示意志、意愿或決心，意為“愿意，要”。will指現(xiàn)在的意愿，would指過去的意愿和決心。(would如表示現(xiàn)在的意愿，語氣較委婉) Please give me another chance, I will never do that again. They said they would help us.will和would2. 表示請求、建議，用于第二人稱的疑問句，would表示更委婉的語氣。 Will/ Would you mind opening the window for me?3. 表示習(xí)慣性動作或某種傾向，意為“總是，習(xí)慣于”。will指現(xiàn)在

6、，would指過去習(xí)慣性動作或傾向。 Fish will die without water. She would sit there for hours, reading a book.would和used to1. 兩者均表示“過去常?！?。2. would僅表示過去的習(xí)慣性動作(不表狀態(tài))，現(xiàn)在有可能還如此，也可能不再那樣。He would take a walk near the forest in the evening. 以前，他晚間常在森林附近散步。3. used to既表示過去的動作也表示過去的狀態(tài)，不過現(xiàn)在不再做或不再有那種狀態(tài)了。He used to take a walk

7、near the forest in the evening.他過去常在晚間到森林附近散步。(而現(xiàn)在已不在那里散步了)shall和should1. shall用于第一、三人稱的疑問句，表示說話人征求對方的意見或向?qū)Ψ秸埵尽?What shall we do this evening? When shall he be able to leave the hospital?2. shall用于第二、三人稱的陳述句，表示說話人給對方命令、警告、允諾、威脅，或按照法律規(guī)定或某個條文規(guī)定要做的事。You shall not leave your seat.(命令)You shall fail if y

8、ou dont work hard.(警告、威脅)He shall have the book when I finish reading it.(允諾)According to the laws, all the money shall be taken back by the government.(條文規(guī)定)shall和should3. should表示勸告或建議,意為“應(yīng)該”,其同義詞為ought to You should keep your promise.4. should表示推測，意為“可能，應(yīng)該”，表示所期待的事幾乎是事實。It is three oclock; the fo

9、otball game should begin now.5. should表示驚訝，意為“竟然”。Its strange that he should have done such a thing. 他竟然做了這樣的事，真是太奇怪了。must和cant2. must表示“必須”，語氣比should, ought to強烈，主要指說話者主觀的命令或強烈的勸告，其否定形式mustnt,表示“禁止，不允許”。以must開頭的一般疑問句的肯定回答中用must，否定回答用neednt或dont have toYou can go out with your friend but you must co

10、me back before 11 at night. Must I finish the paper today? Yes, you must. No, you neednt/ dont have to.must和cant3.must表示感情色彩，意為“偏要，硬要，非得”，常指令人 不快的事情。The car must break down just when I was about to start. 我正要出發(fā)時車偏偏拋錨了。 Im sleeping now. Must you make so much noise? 我在睡覺，你干嘛偏要弄出這么大的聲音？ Naturally, afte

11、r I told her what to do, my daughter must go and do the opposite. 自然地，每次我告訴我女兒該做什么，她非要對著干。 Exercises(2013安徽) It _ be the vocabulary that caused you the problem in the exercise because you know a lot of words. A. may B. couldnt C. should D. neednt根據(jù)“因為你知道很多單詞”推斷出“不可能是詞匯量的問題”所以選B。此處的couldnt應(yīng)為must表示有把握

12、的推測時的否定形式。BExercises2. (2012四川) I got close enough to hear them speaking Chinese, and I said “Ni Hao” just as I _ do in China. A. must B. might C. can D. should句意：我盡量靠近他們，聽到他們在說漢語，我說了一聲“你 好”，就像我在中國時可能做的那樣。might表示對過去情況的推測BExercises3. (2012江蘇) Days later, my brother called to say he was all right, but

13、 _ say where he was. A. mustnt B. shouldnt C. wouldnt D. mightnt句意：幾天后，我哥哥打來電話說他很好，但是就是不愿意說 他在哪兒。will用于否定句，表示“不肯，不樂意”，而句中整體時態(tài)為過去式，故選wouldntmustnt表示“禁止，不允許”，shouldnt表示“不應(yīng)該”，mightnt表示“也許不”CExercises4. (2012遼寧) One of our rules is that every student _ wear school uniform while at school. A. might B. co

14、uld C. shall D. will根據(jù)” One of our rules我們的規(guī)則之一”可以判斷出應(yīng)選shall因為shall用于第二、三人稱的陳述句，表示說話人給對方命令、警告、允諾、威脅，或按照法律規(guī)定或某個條文規(guī)定要做的事。C 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. 表示說話的推測事物的可能性等: eg. Can the news be true? C. 在口語中, can可以表示請求或允許: eg. Can I sit here? can 和could：如：Can you underst

15、and 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的過去式, 表示與過去 有關(guān)的能力和推測: e.g. We all knew that the young man couldnt be a doctor. B. could可以代替can表示請求, 但語氣較can客氣、委婉: e.g. Could you lend me your dictionary? Cou

16、ld I use your bike? 3) can和could接動詞的完成形式，表示可能已經(jīng)做某事。can用在否定和疑問句中, 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提問時，不能再以could或would作答，而應(yīng)該用can或will。如：Could I borrow your dictionary?Yes, of course you can.may 和might ： may 常用來表示： A. 表示請求、允許; 比can較為正式: e.g. May I com

17、e in ? You may go now. B. 表示說話人的猜測: “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，may表示現(xiàn)實的可能性，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. 這條路可能會是不通的。 在疑問句中，表示可能性用can。 如：

18、Where can he be? 他會在哪呢？ C. 表示祝愿;但語氣較正式: e.g. May you succeed! May you have a good journey! might 的用法有: 多在間接引語中表示過去的可能和允許。如: She said that he might take her bike. 她說他可以拿她的自行車去用。 除了在間接引語中以外，might 一般不表示過去的可能或者許可。如要表示過去的可能可以用could, 表示過去的許可可以用was (were) allowed to 或者had permission to 。 表示現(xiàn)在的可能，其可能性要比may

19、小。如： She might go home tomorrow. 說不定他明天會回家。 表示現(xiàn)在的許可, 語氣比may較委婉, 一般用于疑問句(包括間接疑問句), 不可用于肯定句或者否定句。 如: Might I have a word with you? 我可以和你說句話嗎？will和would： 1. will是助動詞或是情態(tài)動詞？ will用于構(gòu)成將來時是助動詞。用于表示“意志”“決心”“請求”是情態(tài)動詞。would亦同理。 e.g. I will tell you something important. 我要告訴你一些重要的事。 （助動詞） Will you tell her tha

20、t Im here? 請您告訴她說我在這兒，好嗎？ （情態(tài)動詞） 2. 在疑問句中用于第二人稱，提出請求或詢問。 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? 請打印這個, 好嗎？ Wont you sit down? 請坐下, 好嗎？ 3. would比will客氣委婉。 e.g.: Would you help us, please? 請您幫助我們，好嗎？（表請求）Id go there with you. 我要和你一塊到那兒去。 Teacher

21、wouldnt allow it. 老師不會允許這件事。（表意愿）（表許可）shall和should： 1. shall用于構(gòu)成將來時是助動詞。 shall用于征求對方的意見，表示 “決心” 是情態(tài)動詞。 e.g.: Perhaps I shall pay a visit to England this winter. 可能今年冬天我會去英國觀光。 （構(gòu)成一般將來時, 助動詞） Shall we go by train, Mom? 媽媽，我們乘火車去好嗎？ （用于征求對方的意見，情態(tài)動詞） I shall go at once. 我必須立即去。 （表 “決心”，情態(tài)動詞） shall可以用于第

22、一、三人稱的疑問句，表示征求意見或許可；還可用于第二、三人稱的陳述句中，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+過去分詞”表示本應(yīng)該在過去做但沒有做。 eg: You should keep your promise. 你應(yīng)該遵守諾言。 She should have passed the exam. 她應(yīng)該通過考試的。must和 haveto1.must用于一般問句中,肯定回答用must否定式用neednt或dont have

23、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 to walk home.2.表示“必須”這個意思時，must和haveto稍有區(qū)別。must著重說明主觀看法，haveto強調(diào)客觀需要。另外，haveto能用于更多時態(tài)。 Youmustbethenewteacher. Hemustbejoking. The

24、reisnobodyhere.Theymusthaveall gonehome. 3.must表示對某人某事的猜測, 作“準(zhǔn)是”, “一定” , 一般用于肯定句中。對過去發(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 was 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 /

25、could, may / might, should和must都可表示肯定的推測。can / could表示客觀可能性；may表示推測時，其語氣不肯定；might語氣更弱，表示某事實際發(fā)生的可能性；should表示確定或可能有的未來或期待；must表示比較肯定的語氣。如：I think advertisements can be quite dangerous.The newcomer may be dismissed by the company.The rescue team should arrive by 5 oclock this afternoon.I think the old

26、woman must be a nice person.could, might, would, should都可表示委婉語氣。如:I wonder if you could let me use your cell phone. Might I know your telephone number? 2. A: _ Xiao 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 _ _.Wouldd like to go with you on SaturdayCouldcouldnt find itExercise 3. A: _ I go with my friend to the harvest festival? B: Yes, you _ _. 4. A: If I want to be a doctor _ I study science? B: Yes, you _. should study scienceMay may go (with your shouldfriends)5. A: He is very