英語語法 情態(tài)動詞2
21.7 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。例如：
Philip may (might) have been hurt seriously in the car accident. 菲力浦可能在車禍中受了重傷。
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。例如：
---Linda has gone to work, but her bicycle is still here. 琳達已經(jīng)去上班了，但她的單車還在這兒。
---She must have gone by bus.肯定乘巴士去的。
3) ought to have done sth, should have done sth表示本應該做某事，而事實上并沒有做。否定句表示不該做某事而做了。例如：
You ought to (should) have been more careful in this experiment. 你當時在做試驗時應該更仔細點。
He ought not to have thrown the old clothes away.他不該把舊衣服扔了。(事實上已扔了。)
ought to 在語氣上比should 要強。
4) neednt have done sth表示本沒必要做某事，但做了。例如：
I dressed very warmly for the trip, but I neednt have done so. The weather was hot.
旅行時，我衣服穿得較多，其實沒有必要。那時天很熱。
5) would like to have done sth表示本打算做某事，但沒做。例如：
I would like to have read the article, but I was very busy then. 我想讀這篇文章，但太忙了一直沒讀。
17.8 21.8 should 和ought to
除了上述的用法，兩者還可表示想必一定，按理應該的意思。例如：
I ought to be able to live on my salary. 靠我的薪水，想必也能維持了。
It ought to be ready now. 想必現(xiàn)在準備好了吧。
They should be there by now, I think. 現(xiàn)在他們該到那兒了。
The poems should be out in a month at most. 詩集估計最多還有一個月就要出版了。
21.9 had better表示最好，相當于一個助動詞，它只有一種形式，它后面要跟動詞原形。例如：
It is pretty cold. Youd better put on my coat. 天相當冷。你最好穿上我的外套。
Shed better not play with the dog. 她最好不要玩耍那條狗。
had better have done sth表示與事實相反的結果，意為本來最好。例如：
You had better have come earlier. 你本該來得早一點。
21.10 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。例如：
If I have a choice, I had sooner not continue my studies at this school. 如果有選擇的余地，我寧可輟學離開這個學校。
I would rather stay here than go home. = I would stay here rather than go home. 我寧愿呆在這兒，而不愿回家。
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。
21.11 will和would
注意：1)would like;would like to do = want to 想要，為固定搭配。例如：
Would you like to go with me? 想和我一塊去嗎?
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。例如：
Would you like some cake? 吃點蛋糕吧。
3)否定結構中用will，一般不用would, wont you是一種委婉語氣。
Wont you sit down? 你不坐下嗎?
21.12 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 neednt
Must you? No, I dont 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。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 ___. Ive told him already.
A. neednt B. wouldnt C. mustnt D. shouldnt
答案A。neednt 不必，不用。 wouldnt 將不, 不會的。 mustnt 禁止、不能。 shouldnt 不應該。本題為不需要，不必的意思，應用neednt。
3)---Dont forget to come to my birthday party tomorrow.
---______.
A. I dont B. I wont C. I cant D. I havent
答案B. will既可當作情態(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。
21.13 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、否定形式應予以注意：
Do they have to pay their bill before the end of the month?
She didnt 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)動詞使用。其他的詞作為實義動詞使用，變疑問，否定時，須有do 等助動詞協(xié)助。
典型例題
Tom ought not to ___ me your secret, but he meant no harm.
A. have told B. tell C. be telling D. having told
答案A。由于后句為過去時，告訴秘密的動作又發(fā)生在其前因，此地應用過去完成時，但它在情態(tài)動詞 ought to 后，所以用have told。
21.14 比較need和dare
這兩詞既可做實義動詞用，又可做情態(tài)動詞用。作為情態(tài)動詞，兩者都只能用于疑問句，否定句和條件句。need 作實義動詞時后面的不定式必須帶to，而dare作實義動詞用時, 后面的to 時常可以被省略。
1) 實義動詞：need(需要, 要求) need + n. / to do sth
2) 情態(tài)動詞：need，只用原形need后加do，否定形式為need not。例如：
Need you go yet? 你要走了嗎?
Yes, I must. / No, I neednt.是的，我要走了/不，不急著走。
21.7 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。例如：
Philip may (might) have been hurt seriously in the car accident. 菲力浦可能在車禍中受了重傷。
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。例如：
---Linda has gone to work, but her bicycle is still here. 琳達已經(jīng)去上班了，但她的單車還在這兒。
---She must have gone by bus.肯定乘巴士去的。
3) ought to have done sth, should have done sth表示本應該做某事，而事實上并沒有做。否定句表示不該做某事而做了。例如：
You ought to (should) have been more careful in this experiment. 你當時在做試驗時應該更仔細點。
He ought not to have thrown the old clothes away.他不該把舊衣服扔了。(事實上已扔了。)
ought to 在語氣上比should 要強。
4) neednt have done sth表示本沒必要做某事，但做了。例如：
I dressed very warmly for the trip, but I neednt have done so. The weather was hot.
旅行時，我衣服穿得較多，其實沒有必要。那時天很熱。
5) would like to have done sth表示本打算做某事，但沒做。例如：
I would like to have read the article, but I was very busy then. 我想讀這篇文章，但太忙了一直沒讀。
17.8 21.8 should 和ought to
除了上述的用法，兩者還可表示想必一定，按理應該的意思。例如：
I ought to be able to live on my salary. 靠我的薪水，想必也能維持了。
It ought to be ready now. 想必現(xiàn)在準備好了吧。
They should be there by now, I think. 現(xiàn)在他們該到那兒了。
The poems should be out in a month at most. 詩集估計最多還有一個月就要出版了。
21.9 had better表示最好，相當于一個助動詞，它只有一種形式，它后面要跟動詞原形。例如：
It is pretty cold. Youd better put on my coat. 天相當冷。你最好穿上我的外套。
Shed better not play with the dog. 她最好不要玩耍那條狗。
had better have done sth表示與事實相反的結果，意為本來最好。例如：
You had better have come earlier. 你本該來得早一點。
21.10 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。例如：
If I have a choice, I had sooner not continue my studies at this school. 如果有選擇的余地，我寧可輟學離開這個學校。
I would rather stay here than go home. = I would stay here rather than go home. 我寧愿呆在這兒，而不愿回家。
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。
21.11 will和would
注意：1)would like;would like to do = want to 想要，為固定搭配。例如：
Would you like to go with me? 想和我一塊去嗎?
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。例如：
Would you like some cake? 吃點蛋糕吧。
3)否定結構中用will，一般不用would, wont you是一種委婉語氣。
Wont you sit down? 你不坐下嗎?
21.12 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 neednt
Must you? No, I dont 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。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 ___. Ive told him already.
A. neednt B. wouldnt C. mustnt D. shouldnt
答案A。neednt 不必，不用。 wouldnt 將不, 不會的。 mustnt 禁止、不能。 shouldnt 不應該。本題為不需要，不必的意思，應用neednt。
3)---Dont forget to come to my birthday party tomorrow.
---______.
A. I dont B. I wont C. I cant D. I havent
答案B. will既可當作情態(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。
21.13 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、否定形式應予以注意：
Do they have to pay their bill before the end of the month?
She didnt 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)動詞使用。其他的詞作為實義動詞使用，變疑問，否定時，須有do 等助動詞協(xié)助。
典型例題
Tom ought not to ___ me your secret, but he meant no harm.
A. have told B. tell C. be telling D. having told
答案A。由于后句為過去時，告訴秘密的動作又發(fā)生在其前因，此地應用過去完成時，但它在情態(tài)動詞 ought to 后，所以用have told。
21.14 比較need和dare
這兩詞既可做實義動詞用，又可做情態(tài)動詞用。作為情態(tài)動詞，兩者都只能用于疑問句，否定句和條件句。need 作實義動詞時后面的不定式必須帶to，而dare作實義動詞用時, 后面的to 時常可以被省略。
1) 實義動詞：need(需要, 要求) need + n. / to do sth
2) 情態(tài)動詞：need，只用原形need后加do，否定形式為need not。例如：
Need you go yet? 你要走了嗎?
Yes, I must. / No, I neednt.是的，我要走了/不，不急著走。
