情態(tài)動(dòng)詞
can , could , may , might , must , shall , will , would , need , dare , dared , should , ought to , used to; had better; would rather
情態(tài)動(dòng)詞表猜測(cè)
1) should / ought to 照說(shuō)應(yīng)該，估計(jì) The photo should be ready by 12 o’clock .
2) may / might / must / can’t / couldn’t 表猜測(cè)，
a.非常肯定的猜測(cè)
must “肯定, 一定” can’t “肯定不,不可能”He must be at home now.
He must like English. He can’t be at home now.
He can’t have much money.
注意: mustn’t “不準(zhǔn),禁止”You mustn’t talk in class.
b.表示不太肯定的猜測(cè)： may/might 可能 may not, might not 可能不
can/could 只用于疑問(wèn)句和否定句中
You may not remember me. I thought he might remember me.
---Can it be true.? --- No, it can’t true.
could/might 表示過(guò)去，但也可表示現(xiàn)在，表示現(xiàn)在時(shí)，它的可能性比can/ may要小。
He may/might be in Class One .
注意1：表猜測(cè)時(shí)，時(shí)態(tài)體現(xiàn)在情態(tài)動(dòng)詞后面
a.對(duì)過(guò)去的猜測(cè)-情態(tài)動(dòng)詞后面用完成時(shí)
1 He must have read books about Shakespeare because he knows so much about him.
2 -- I called him last night, but nobody answered.
--He can’t /couldn’t have been at home.
3 In those days I may have been pretty.
b.對(duì)現(xiàn)在的猜測(cè) ---情態(tài)動(dòng)詞后面用動(dòng)詞原形或進(jìn)行式。
1 He can’t like this kind of book.
2 They may be playing football now.
注意2 :a。may / might / must / can’t / couldn’t 表猜測(cè)時(shí)的反意疑問(wèn)句。
He might have a lot of work to do now , doesn’t he ?
He may have missed the early bus , hasn’t he ?
I must have been asleep when you rang me , wasn’t I ?
It can’t rain tomorrow , will it ?
He must be studying in the classroom now , isn’t he ?
b．can 表猜測(cè)一般用于否定句或疑問(wèn)句中，在肯定句中往往表示“一時(shí)的可能性”
“有時(shí)可能會(huì)”
Training by yourself can be highly dangerous .
二）情態(tài)動(dòng)詞表虛擬
could have done 本可以-----
may/might have done 本來(lái)可能---
should / ought to have done 本來(lái)應(yīng)該---- shouldn’t/ought not to have done本不該---
needn’t have done 本不必----
wouldn’t have done 本不會(huì)---
1 Chuck also learns that he should have cared more about his friends .
2 You needn’t have come here so early.
3.You needn’t have gone there yesterday .
4.We ought to have given you more help , but we were so busy .
5.We could have walked to the station , it was so near .
****三）幾組詞的區(qū)別
1）can , be able to a.. can 只有現(xiàn)在式和過(guò)去式，而be able to 有各種時(shí)態(tài)，
b. can 表能力，be able to 表成功地完成某一具體動(dòng)作，相當(dāng)于manage to do ,succeed in doing
Below the 11th floor people were able to escape .
2) must , have to have to “必須，不得不”表客觀需要
must 表說(shuō)話人的主觀看法
3）would , used to 兩者都可以表示過(guò)去的習(xí)慣。但would表示過(guò)去反復(fù)發(fā)生的動(dòng)作或過(guò)
去的一種傾向，現(xiàn)在可能還存在，而used to表示現(xiàn)在不復(fù)存在的過(guò)去的狀態(tài)、情況和動(dòng)
作。
Often he would hear a long low whistle and the sound of a metallic noise .
I used to have an old jeep .
** 注意的否定和疑問(wèn)句，
Used you to go to the same school ? = Did you use to go to the same school ?
I usedn’t to smoke . = I didn’t use to smoke .
4) need , dare 作為情態(tài)動(dòng)詞，一般用于否定句，疑問(wèn)句，條件句中(除 I dare say ----)，
沒(méi)有人稱和數(shù)的變化，否定句在其后加not ，疑問(wèn)句把need , dare ,dared 提前，后面接
動(dòng)詞原形。***除了在I dare say---這種習(xí)慣用語(yǔ)中
---If you die ,who will get your money?----I dare say my uncle will.
而作為及物動(dòng)詞時(shí)，有人稱、數(shù)和時(shí)態(tài)的變化，否定句，疑問(wèn)句要借助于助動(dòng)詞do ,
does ,did 。跟不定式作賓語(yǔ)。
She dare not say what she thinks . = She doesn’t dare to say what she thinks .
You don’t need to read the book if you don’t want to.
5)will 1）表示說(shuō)話時(shí)做出某種決定時(shí). ---- The phone is ringing . ----- I’ll answer it .
2) 表示一種傾向、習(xí)慣性動(dòng)作或說(shuō)話人的揣測(cè)的意見。
Without water flowers will die . After supper, he will have tea.
6).shall 1）用于第一人稱，表示將來(lái)，
2）用于第一、三人稱，在問(wèn)句中表示征求別人的意見或向?qū)Ψ秸?qǐng)示
-----Shall he wait outside or come in ?
3）用于第二、三人稱，表示說(shuō)話人對(duì)對(duì)方的命令、警告、允諾、威脅、決心。
He shall have the book when I finish reading .