如何分辨Must / Should / Have to / Could

must

1. (表示必要,命令或強制)必須,得
You mustn't talk like that.
你可不能這樣說話。
You must do as you are told.
你必須遵囑行事。
We must be home by six.
我們必須在六點以前回家。
2. (表示肯定的推測)一定是,諒必,八成
This must be your room.
這一定是你的房間了。
He must be eighty now.
他現在八成有八十歲了。
3. (表示不可避免性)必然要,必定會
All men must die.
人總有一死。
4. (表示主張)一定要,堅持要
If you must go, at least wait till the rain stops.
如果你堅持要走,至少也要等雨停了再走。
5. (表示與說話人願望相反)偏要
The machine must break down at this busy hour.
正忙的時候機器偏偏壞了。
n.[S]
1. 必須做的事;不可少的事物
A walking stick is a must for me now.
如今我行走離不開手杖了。
2. 一定要看(或聽,讀)的東西
a.
1. 絕對必要的,必須的[B]

must2
KK: []
DJ: []

n.
1. 葡萄液,果汁[U]

must3
KK: []
DJ: []
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should

1. (shall的過去式,表示過去將來)將
We hoped that we should be able to do that.
我們希望我們能這樣做。
2. (表示語氣較強的假設)萬一,竟然
If the car should break down on the way, you would have to walk back.
萬一汽車中途拋錨,你就得走回來。
3. (表示可能性,推測,推論或期待)可能,該
She should be here any minute.
她該馬上就到。
Dinner should be ready by now.
此刻晚飯應該做好了。
4. (表示義務,責任)應該,應當
You should do as she says.
你應當照她說的去做。
He should work harder.
他應該更加努力。
You should help your mother with the housework.
你應該幫你母親做家務。
5. (表示委婉,謙遜)可,倒
6. (表示感情,意志等)竟然會;應該
I'm sorry it should be this way.
很遺憾,事情竟會是這個樣子。
It's strange that he should be absent.
真奇怪,他竟會缺席。
You shouldn't have told him about it.
你不該把這件事告訴他的。
7. (表示建議,命令,決定等)應該,必須
Crime should be punished.
犯罪應受懲罰。
8. (表示目的)會,可以
He stood away so that we should enter the room first.
他讓開一步,讓我們先進屋。
9. (表示結果,意願等)就,該
10. (表示徵求同意等)可以,該
Who should I see about my schedule?
關於我的日程該和誰商討?

n.
1. 霉;發霉[U]
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have to

1. 必須

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could

1. can的過去式
She could play the violin when she was five.
她五歲時便能拉小提琴了。
2. (用於假設語氣,表示與事實相反的設想)能,可以
I wish I could go to France.
但願我能去法國。
I would go if I could.
能去我就去。
3. (表示可能性)可能
That could be my train.
那可能是我要乘的火車。
4. (用於婉轉語氣)能,可以
Could I smoke here?
我可以在這裡抽煙嗎?
Couldn't you try it again?
你可否再試一下?

have to