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(shí)，語(yǔ)氣由 should(應(yīng)該)、had better最好)、must(必須)漸強(qiáng)。
had better表示"最好"
had better 相當(dāng)于一個(gè)助動(dòng)詞，它只有一種形式，它后面要跟動(dòng)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(shí)相反的結(jié)果，意為"本來(lái)最好"。
You had better have come earlier.
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 ratherB. would you rather C. will you rather D. should you rather
答案B。本題考查情態(tài)動(dòng)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。
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(qǐng)求勸說(shuō)時(shí)，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(yǔ)氣。
Won’t you sit down?
情態(tài)動(dòng)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. mightB. will C. can D. should
答案C.could表示委婉的語(yǔ)氣，并不為時(shí)態(tài)。答語(yǔ)中of course，表示肯定的語(yǔ)氣，允許某人做某事時(shí)，用can和 may來(lái)表達(dá)，不能用could或might。復(fù)習(xí)： will 與you連用，用來(lái)提出要求或下命令。should與you 連用，用來(lái)提出勸告。
2)---Shall I tell John about it?
---No, you ___. I’ve told him already.
A. needn’tB. wouldn’tC. mustn’tD. shouldn’t
答案A。needn’t 不必，不用。 wouldn’t 將不, 不會(huì)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’tD. I haven’t
答案B.will既可當(dāng)作情態(tài)動(dòng)詞，表請(qǐng)求、建議、也可作為實(shí)義動(dòng)詞表"意愿、意志、決心"，本題表示決心，選B。
帶to 的情態(tài)動(dòng)詞
帶to 的情態(tài)動(dòng)詞有四個(gè)：ought to, have to, used to, be to, 如加上have got to ,(=must), be able to，為六個(gè)。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.
You ought not to have told her all about it.
Ought he to see a heart specialist at once.?
ought to 本身作為情態(tài)動(dòng)詞使用。其他的詞作為實(shí)義動(dòng)詞使用，變疑問，否定時(shí)，須有do 等助動(dòng)詞協(xié)助。
典型例題
Tom ought not to ___ me your secret, but he meant no harm.
A.have toldB.tellC.be tellingD. having told
答案A。由于后句為過(guò)去時(shí)，告訴秘密的動(dòng)作又發(fā)生在其前因，此地應(yīng)用過(guò)去完成時(shí)，但它在情態(tài)動(dòng)詞 ought to 后，所以用have。
比較need和dare
這兩詞既可做實(shí)義動(dòng)詞用，又可做情態(tài)動(dòng)詞用。作為情態(tài)動(dòng)詞，兩者都只能用于疑問句，否定句和條件句。 need 作實(shí)義動(dòng)詞時(shí)后面的不定式必須帶to，而dare作實(shí)義動(dòng)詞用時(shí), 后面的to 時(shí)常可以被省略。
1) 實(shí)義動(dòng)詞： need(需要, 要求)
need + n. / to do sth
2) 情態(tài)動(dòng)詞： need，只用原形need后加do，否定形式為need not。
Need you go yet?
Yes, I must. / No, I needn’t.
3) need 的被動(dòng)含義：need, want, require, worth(形容詞)后面接doing也可以表示被動(dòng)：
need doing = need to be done
