情態(tài)動(dòng)詞

　　情態(tài)動(dòng)詞是高考的重點(diǎn)考查項(xiàng)目，對(duì)學(xué)習(xí)情態(tài)動(dòng)詞的要求是：

　　首先、了解情態(tài)動(dòng)詞各自的基本意義及用法，然后掌握情態(tài)動(dòng)詞表示推測(cè)的用法（其中重點(diǎn)是對(duì)表過(guò)去推測(cè)的用法）還要注意帶有情態(tài)動(dòng)詞的反意疑問(wèn)句的用法。

　　情態(tài)動(dòng)詞的特征：

　　1.本身有詞義，但完全。因此不能獨(dú)立作謂語(yǔ)，只能和動(dòng)詞原形一起構(gòu)成謂語(yǔ)。

　　2.后接動(dòng)詞不定式一律不帶to

　　3.不隨人稱和數(shù)的變化。

　　情態(tài)動(dòng)詞各自的基本意義及用法

　　表一、can 與could用法對(duì)比表

　　對(duì)比點(diǎn) can could

　　1、表“能力” Can you lift this heavy box? I couldn’t understand what he said at all.

　　2、表“許可” You can use a different material instead. He said I could borrow his bike.

　　3、“懷疑” No, no, it can’t be true.

　　What on earth can this mean? We thought the story could not be true. How could you be so careless?

　　4、can與be able to 區(qū)別 1. could代替 can，表示語(yǔ)氣更為婉轉(zhuǎn)。

　　Eg. Could I use your bike? Yes, I can

　　2. can (能夠)=be able to(僅表能力時(shí))，但be able to 表示一番努力后，才能做得到，且有更多的時(shí)態(tài)。

　　He was a good swimmer, so he __________ swim to the river bank when the boat sank.

　　A. could B. might C. shall D. was able to

　　表二、may與 might用法對(duì)比表

　　對(duì)比點(diǎn) may Might

　　1．表“詢問(wèn)” May I …?(=Can I …?) Might I …?(=Could I…?)(但比用may 更客氣)

　　2.表“允許” You may take the boy there. He told me he might come .(might 與told相呼應(yīng))

　　3．表“可能”“或許” She may nor like this place. I’m afraid he might not like this play.

　　注： 1. May I…?的答語(yǔ)。

　　2.may可表示期望或祝愿

　　May you succeed !

　　3.may (might)用于目的狀語(yǔ)從句中 肯定：Yes, you may.

　　否定：No, you mustn’t 不行（語(yǔ)氣強(qiáng)硬）

　　No, you may not 或No, you’d better not.

　　The emperor gave them some gold in order that they might begin their work at once.

　　表三、must與have to的用法對(duì)比表

　　對(duì)比點(diǎn) must have to 

　　1．表“必須” （主觀看法）必須；沒(méi)有過(guò)去式，可用于間接引語(yǔ)中。He told me I must do according to what he said. （客觀需要）不得不，有多種時(shí)態(tài)。It’s raining heavily, we can’t go now.

　　2.疑問(wèn)句 Must I …?

　　Yes, you must.（一定）

　　No, you needn’t./ you don’t have to.(不必) Do you have to go today?

　　Yes, we do.

　　否定句：You don’t have to worry about that.

　　表四、need與dare的用法對(duì)比表

　　對(duì)比點(diǎn) need dare

　　1.情態(tài)動(dòng)詞+動(dòng)詞原形

　　1）否定式

　　2）疑問(wèn)式 He need not (needn’t)go.

　　----Need we do it again?

　　---No, you needn’t do it again. He dare not say so.

　　Dare she go out alone at night?

　　How dare you say I’m unfair?

　　If he dare do that, he’ll be punished.(條件句)

　　I dare say.(固定用法)

　　2.行為動(dòng)詞+帶to不定式 

　　1）肯定式

　　2）否定式

　　3）疑問(wèn)式 He needs to go.

　　He doesn’t (does not)need to go.

　　Does he need to do it again?

　　No, he doesn’t need ot do it again. He dares to say.

　　He does not(doesn’t)dare to say.

　　If you dare to jump into the water from here, so dare I .

　　3. did not need to do

　　表示過(guò)去沒(méi)有必要做 She didn’t need to attend the meeting yesterday, and she stayed with her children.(她沒(méi)有參加)

　　表五、should與ought to用法對(duì)比表

　　對(duì)比點(diǎn) should ought to

　　1、表“應(yīng)該” 表勸告、建議

　　You should listen to the doctor’s advice.

　　We should learn from Zhang Hua 表示“有責(zé)任有必要”做某事

　　You ought to finish your work before you go home.

　　We ought to help each other. 

　　2、表“估計(jì)”

　　They should get home by now. 表示“非常可能”的事，可譯為“總應(yīng)該”

　　If we start to work right now, we ought to finish it before lunch.(午飯前應(yīng)當(dāng)能干完)

　　注： 1）、should還可在虛擬語(yǔ)氣中的使用

　　2). 注意：ought to的疑問(wèn)式及否定式

　　----Ought he to go? ----Yes, I think he ought to.

　　No, he oughtn’t to.

　　否定式：ought not to a或oughtn’t to do(不說(shuō)ought to not do)

　　反疑問(wèn)句：oughtn’t ______?

　　表六、shall與will的用法對(duì)比表

　　shall Will

　　1. 征詢對(duì)方意見(jiàn)或請(qǐng)求指示，用于第一、三人稱：

　　Shall I (we)…?

　　Shall he (she)…?

　　Where shall I (we)wait for you? 1． 詢問(wèn)對(duì)方的意思或向?qū)Ψ教岢鲆�求�?/p>

　　Will you(please)…? Won’t you…?

　　Would you like to…?(用would替代will更客氣) 

　　----Won’t you go and see the film?你不去看電影嗎？---Yes, I think I will. 不， 我想去。

　　2. 表示說(shuō)話人的“意愿”有“命令”“警告”“強(qiáng)制”“允諾”“決心”等，用于第二、三人稱，要重讀。

　　You shall do what I tell you ( to do).

　　我叫你干什么你就干什么。

　　Everything shall be done to save the ship.

　　一定要竭盡全力來(lái)拯救這艘船。 表示“意志”“意愿”，用于各種人稱：

　　I won’t do anything you don’t like.

　　我不會(huì)做任何你不喜歡的事。

　　Would表示過(guò)去時(shí)間的“意志”“意愿”

　　Shylock would not take the money earlier.

　　夏洛克先前是不肯要錢的。

　　表七：used to與would用法對(duì)比表

　　used to would

　　1.表示過(guò)去的動(dòng)作、狀態(tài)，重在與現(xiàn)在情況的對(duì)比，不一定要有時(shí)間狀語(yǔ)。

　　I used to play cards a lot, but now I seldom play.

　　My hometown is not what it used to be. 1.只表示過(guò)去動(dòng)作的重復(fù)，有明確的時(shí)間狀語(yǔ)

　　I would go to see my grandfather on Sunday when he was in the middle school.

　　2.would 后只接表動(dòng)作的動(dòng)詞，不接表認(rèn)識(shí)或狀態(tài)動(dòng)詞

　　He used to be nervous in the exam. 

　　2.表示過(guò)去的習(xí)慣有時(shí)可互換：

　　When we were very young, we used to / would go skating every winter.

　　2. 表示過(guò)去的次數(shù)時(shí)，不能使用：

　　( √）We went to the Great Wall five times when we were young.

　　( X ) We used to go / would go to the Great Wall five times when we were young.

　　注：used to do的否定式：usedn’t to do 或didn’t use to do (usedn’t也可寫(xiě)作usen’t)

　　疑問(wèn)式： Did you use to do ? Didn’t you use to do?

　　Used you to do? Usedn’t you to do?

　　情態(tài)動(dòng)詞表推測(cè)

　　情態(tài)動(dòng)詞表推測(cè)的意義：

　　1、大多數(shù)情態(tài)動(dòng)詞（除表‘能力、許可、意志’外），都可以表示推測(cè)，其程度有差異。按其可能性程度的高低排列為：

　　Must ﹥will ﹥would ﹥ought to ﹥ should ﹥ can ﹥ could﹥ may ﹥ might

　　肯定 完全可能 很可能 可能 有可能

　　2.注意區(qū)分情態(tài)動(dòng)詞的否定的含義：

　　may not或許不、可能不 might not可能不 can’t 不可能

　　mustn’t不許、禁止 shouldn’t不應(yīng)該 needn’t 不必

　　3.情態(tài)動(dòng)詞表推測(cè)具體運(yùn)用：情態(tài)動(dòng)詞可以對(duì)現(xiàn)在、進(jìn)行、過(guò)去推測(cè)

　　S主+情態(tài)動(dòng)詞+be+adj 對(duì)“性質(zhì)”“特征”的推測(cè)

　　S主+情態(tài)動(dòng)詞+be+n 對(duì)“職業(yè)”“事物”的推測(cè)

　　S主+情態(tài)動(dòng)詞+V原 對(duì)經(jīng)常性行為的推測(cè)

　　S主+情態(tài)動(dòng)詞+be+V-ing 對(duì)進(jìn)行著的行為的推測(cè)

　　S主+情態(tài)動(dòng)詞+have+PP 對(duì)過(guò)去的行為的推測(cè)

　　特別提醒：情態(tài)動(dòng)詞表推測(cè)時(shí)

　　1、 can只能用于否定句和疑問(wèn)句

　　2、 must只能用于肯定句（它的否定句和疑問(wèn)句其實(shí)就用can來(lái)代替了）

　　3、 如句中有情態(tài)動(dòng)詞 + 完成時(shí)，定是對(duì)過(guò)去的推測(cè) 。

　　4、 句中如有表示不肯定的話語(yǔ)，如：I am not sure; I don’t know 之類，常選may /might的各種形式

　　4. 記住下面幾組表示反勸的特殊的表推測(cè)的形式

　　1). could + have + PP表示本來(lái)能做到，但事實(shí)上沒(méi)有做到。 He could have finished the task on time, but the heavy snow came.

　　2). couldn’t +have + PP表示本來(lái)不能做到，但已經(jīng)做到了。 She could not have covered the whole distance, but in fact she arrived ahead of time.

　　3) needn’t + have + pp表示本不必做的，但已經(jīng)做到了。 She needn’t have attended the meeting yesterday, but she did.

　　4.) should/ought to +have + PP表示 該做而沒(méi)有做 The plant is dead. I should/ought to have given ot more water.

　　5) shouldn’t/ oughtn’t to +have + PP表示 不該做而做了。 You oughtn’t to / shouldn’t have taken her bike without permission.

　　5. 記住下面對(duì)比表：

　　must只能用于肯定句（它的否定句和疑問(wèn)句其實(shí)就用can來(lái)代替了）

　　1.must + have + PP 表示對(duì)過(guò)去肯定的推測(cè)，譯為“一定是，準(zhǔn)是” The road is wet. It must have rained yesterday.

　　2.can + have + PP 表示對(duì)過(guò)去的推測(cè)（限于問(wèn)句中） Can she have said so? 他可能這樣說(shuō)嗎？

　　3.can’t + have + PP 表示對(duì)過(guò)去的否定推測(cè) He cannot have said such a foolish thing.

　　情態(tài)動(dòng)詞表推測(cè)的反意疑問(wèn)句

　　情態(tài)動(dòng)詞表推測(cè)的反意疑問(wèn)句，簡(jiǎn)單來(lái)說(shuō)，就是以情態(tài)動(dòng)詞后的時(shí)態(tài)為淮，如句子里有明確的時(shí)間狀語(yǔ)，則以其為準(zhǔn)。以 must 為例：

　　eg. 1. You must be hungry now, aren’t you?

　　2. He must be watching TV , isn’t he ?

　　3 Tom must have lived her for a long time, hasn’t he ?

　　4. She must have arrived yesterday, didn’t she?

　　注：如選擇題中（以She must have arrived yesterday, didn’t she？為例）既有didn’t she又有hasn’t she則以didn’t she？為最佳答案。