博思考試情態(tài)動詞的使用技巧

　　Mike can’t have found his car, for he came to work by bus this morning.

　　邁克一定還沒有找回他的車，因為早上他是坐公共汽車來上班的。

　　注意：could, might表示推測時不表示時態(tài)，其推測的程度不如 can, may。

　　七、情態(tài)動詞+ have +過去分詞

　　1.may(might) have + done sth, can (could) have + done sth　表示過去，推測過去時間里可能發(fā)生的事情。

　　Philip may (might) have been hurt seriously in the car accident.

　　Philip can (could) have been hurt seriously in the car accident.

　　2.must have +done sth，對過去時間里可能發(fā)生的事情的推測，語氣較強，具有"肯定"，"諒必"的意思。

　　--- Linda has gone to work, but her bicycle is still here.

　　---She must have gone by bus.

　　3.ought to have done sth, should have done sth

　　本應(yīng)該做某事，而事實上并沒有做。否定句表示"不該做某事而做了"。

　　You ought to (should) have been more careful in this experiment.

　　He ought not to have thrown the old clothes away.(事實上已扔了。)

　　ought to 在語氣上比should 要強。

　　4.needn’t have done sth　本沒必要做某事

　　I dressed very warmly for the trip, but I　needn’t have done so. The weather was hot.

　　5.would like to have done sth　本打算做某事

　　I would like to have read the article, but I was very busy then.

　　八、should 和ought to

　　should 和ought to 都為"應(yīng)該"的意思，可用于各種人稱。

　　---Ought he to go?

　　---Yes. I think he ought to.

　　表示要求，命令時，語氣由 should(應(yīng)該)、had better最好)、must(必須)漸強。

　　九、 had better表示"最好"

　　had better 相當(dāng)于一個助動詞，它只有一種形式，它后面要跟動詞原形。

　　had better do sth

　　had better not do sth

　　It is pretty cold. You’d better put on my coat.

　　She’d better not play with the dog.

　　had better have done sth表示與事實相反的結(jié)果，意為"本來最好"。

　　You had better have come earlier.

　　十、 would rather表示"寧愿"

　　would rather do

　　would rather not do

　　would rather… than…　寧愿……而不愿。

　　還有would sooner, had rather, had sooner都表示"寧愿"、"寧可"的意思。

　　If I have a choice, I had sooner not continue my studies at this school.

　　I would rather stay here than go home. = I would stay here rather than go home.

　　典型例題

　　---- Shall we go skating or stay at home?

　　----Which ___ do?

　　A. do you rather　B. would you rather　C. will you rather　D. should you rather

　　答案B。本題考查情態(tài)動詞rather的用法，would rather +do sth 意為"寧愿"，本題為疑問句， would 提前，所以選B。

　　十一、will和would

　　注意：

　　1.would like; Would like to do = want to 想要，為固定搭配。

　　Would you like to go with me?

　　2.Will you…?　Would you like…? 表示肯定含義的請求勸說時，疑問句中一般用some, 而不是any。

　　Would you like some cake?

　　3.否定結(jié)構(gòu)中用will，一般不用would, won’t you是一種委婉語氣。

　　Won’t you sit down?

　　十二、情態(tài)動詞的回答方式

　　問句　肯定回答　否定回答

　　Need you…?　Yes, I must.　No,I needn’t

　　Must you…?　/don’t have to.

　　典型例題

　　1.---Could I borrow your dictionary?

　　---Yes, of course, you____.

　　A. might　B. will　C. can　D. should

　　答案C.could表示委婉的語氣，并不為時態(tài)。答語中of course，表示肯定的語氣，允許某人做某事時，用can和 may來表達，不能用could或might。復(fù)習(xí)： will 與you連用，用來提出要求或下命令。should與you 連用，用來提出勸告。

　　2.---Shall I tell John about it?

　　---No, you ___. I’ve told him already.

　　A. needn’t　B. wouldn’t　C. mustn’t　D. shouldn’t

　　答案A。needn’t 不必，不用。 wouldn’t 將不, 不會的。 mustn’t 禁止、不能。 shouldn’t　不應(yīng)該。本題為不需要，不必的意思，應(yīng)用needn’t。

　　3.---Don’t forget to come to my birthday party tomorrow.

　　---______.

　　A. I don’t　B.　I won’t　C. I can’t　D. I haven’t

　　答案B.　will既可當(dāng)作情態(tài)動詞，表請求、建議、也可作為實義動詞表"意愿、意志、決心"，本題表示決心，選B。

　　十三、帶to 的情態(tài)動詞

　　帶to 的情態(tài)動詞有四個：ought to, have to, used to, be to, 如加上have got to ,(=must), be able to，為六個。它們的疑問，否定形式應(yīng)予以注意：

　　Do they have to pay their bill before the end of the month?

　　She didn’t use to play tennis before she was fourteen.