學(xué)習(xí)重點(diǎn)：Modals:must 情態(tài)動(dòng)詞must
Modals: can 情態(tài)動(dòng)詞can
Modals: need 情態(tài)動(dòng)詞need
Modals: must 情態(tài)動(dòng)詞must
我們已經(jīng)嘗過(guò)了表示義務(wù)的must和have to。在現(xiàn)在時(shí)里面可能使用must和have to，但在其他時(shí)態(tài)里只能have to。
Postive Obligation 表示肯定意思的和義務(wù)（時(shí)態(tài)）
現(xiàn)在 主語(yǔ)+must+動(dòng)詞*
主語(yǔ)＋have to +動(dòng)詞
主語(yǔ)+have got to +動(dòng)詞
將來(lái) 主語(yǔ)+will+have to +動(dòng)詞
主語(yǔ)+be going to =have to +動(dòng)詞
We will have to see
He is going to have to drive
過(guò)去 主語(yǔ)+had to +動(dòng)詞
You had to resign.
現(xiàn)在完成 主語(yǔ)+have tp +動(dòng)詞
I have had to stop
She has had to sing.
Negative Obligation 表示否定意思的責(zé)任和義務(wù)
表示否定的義務(wù)，即禁止時(shí)，在現(xiàn)在時(shí)里可以用must,而在其他時(shí)態(tài)里則必須用be forbidden to 或not be allowed等。
現(xiàn)在 主語(yǔ)+must not(mustn’t )+動(dòng)詞
You mustn’t leave.
將來(lái) 主語(yǔ)+will be forbidden to+動(dòng)詞
主語(yǔ)+be going to be forbidden to +動(dòng)詞
主語(yǔ)+will not be allowed to +動(dòng)詞
主語(yǔ)+be not going to be allowed to +動(dòng)詞
You will be forbidden to leve.
You are going to be forbidden to leave.
He will not be allowed to eat.
He’s not going to be allowed to eat.
過(guò)去 主語(yǔ)+was/were forbidden to +動(dòng)詞
主語(yǔ)+was /were not allowed+動(dòng)詞
I was forbidden to speak
We were not allowed to see.
現(xiàn)在完成 主語(yǔ)+have been forbidden to+動(dòng)詞
主語(yǔ)+have not been allowed to +動(dòng)詞
He has beren forbidden to move.
They have not been allowed to talk.
No Obligation不做……也行
現(xiàn)在 主語(yǔ)+do not have to +動(dòng)詞
主語(yǔ)+have not got to +動(dòng)詞
I don’t have to go.
She hasn’t got to look.
將來(lái) 主語(yǔ)+will not（won’t)+have to +動(dòng)詞
主語(yǔ)+be not going to =have to +動(dòng)詞
I won’t have to lie.
We aren’t going to have to move.
過(guò)去 主語(yǔ)+did not have to+動(dòng)詞
She didn’t have to dance.
現(xiàn)在完成 主語(yǔ)+have not had to +動(dòng)詞
I haven’t had to work.
*此處指動(dòng)詞原型，也就是不加to的不定式。
Modals: can 情態(tài)動(dòng)can
Expressing permission表示許可
現(xiàn)在時(shí)里可以用can, 過(guò)去時(shí)和條件時(shí)態(tài)里要用could,而其他時(shí)態(tài)里必須用be allowed to ,be permitted to 等表達(dá)。
現(xiàn)在：主語(yǔ)+can+動(dòng)詞
主語(yǔ)+be+allowed/permitted +to+動(dòng)詞
I can go .
She’s allowed/permitted to leave.
過(guò)去：主語(yǔ)+could動(dòng)詞
主語(yǔ)+was/were +allowed/permitted +to +動(dòng)詞
We could see.
It was permitted/allowed to continue.
將來(lái)：主語(yǔ)+will be allowed to +動(dòng)詞
主語(yǔ)+be+going to be allowed/permitted to +動(dòng)詞
I will be allowed/permitted to travel.
We are going to be permitted/allowed to attend.
條件：主語(yǔ)+could+動(dòng)詞
主語(yǔ)+would be +allowed/permitted +to +動(dòng)詞
He could do it.
We would be allowed/permitted to visit.
Expressing Ability 表示能力
現(xiàn)在時(shí)態(tài)里可以用can,過(guò)去時(shí)態(tài)和條件時(shí)態(tài)里要用could, 而其他時(shí)態(tài)里必須用be able to.
現(xiàn)在：主語(yǔ)+can +動(dòng)詞
主語(yǔ)+be able to +動(dòng)詞
I can dance.
We are able to sing.
過(guò)去：主語(yǔ)+could +動(dòng)詞
主語(yǔ)+was/were+able to+動(dòng)詞
You could draw.
They were able to choose.
將來(lái)：主語(yǔ)+will be able to +動(dòng)詞
主語(yǔ)+be going to be able to+動(dòng)詞
We will be able to fly.
She is going able to travel.
條件；主語(yǔ)+could+動(dòng)詞
主語(yǔ)+would be able to +動(dòng)詞]
They could drive.
He would be able to work.
Expressing possibility 表示可能性
在現(xiàn)在時(shí)態(tài)里用can,過(guò)去時(shí)里用could。
The weather can be very cold at this time fo year.每年這個(gè)時(shí)候都很冷。In the old days, the people of bognor could be very aggressive. 在古代，伯格諾人是非常好斗的。
Modals:need 情態(tài)動(dòng)詞need
Need后面加不定式，可以變成表示“有必要”的情態(tài)動(dòng)詞“。
在現(xiàn)時(shí)態(tài)里，它和一般動(dòng)詞一樣，接在單數(shù)第三人稱后面，要加-s;在否定句、疑問(wèn)句里要用do/does.
*19\20單元里，為了方便起見(jiàn)，我們把意思上類似情態(tài)動(dòng)詞的表達(dá)（have need to ）稱作情態(tài)動(dòng)詞。
●肯定句 I need to see you.我應(yīng)該去見(jiàn)你。
He needs to see you.他應(yīng)該去你。
●疑問(wèn)句 Do you need to come? 你一定要來(lái)嗎？
Does he need to come?他一定要來(lái)嗎？
●否定句：You don’t need to come.你不一定要來(lái)。
He doesn’t need to come. 他不一定要來(lái)。
或者： You needn’t come.
He needn’t come.
即使在單數(shù)第三人稱后，needn’t 也不參加-s,而且它后面接的是不加to的不定式。
它的過(guò)去時(shí)和將來(lái)時(shí)的方法和一般動(dòng)詞一樣。
They needed to talk to you.
Did rhey need to talk to you?
They didn’t need to talk to you.
They will need to talk to you.
They are going to need to talk to you.
Will they need to talk to you?
Are they going to need to talk to you?
They won’t need to talk to you.
They ‘re not going to need to talk to you.
英國(guó)英語(yǔ)里還有needn’t have 這種過(guò)[的表達(dá)方法，表示的是“雖然沒(méi)必要做，但還是做了”。
You needn’t have told him the truth.你不應(yīng)該告訴他實(shí)情。
