ought to與should意思接近,大多數(shù)情況下二者可以互換,但是should談的是自己的主觀看法,ought to則更多反映客觀情況,在談到法律、義務和規(guī)定時使用.
如：We should／ought to help each other and learn from each other in our work．
She is your mother,so you ought to support her．
We ought to go and see Mary tomorrow,but I don’t think we will．
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一、ought to具體用法如下：
1.(表示義務、責任等) 應當,應該
You ought to work harder than that.
2.(表示勸告、建議等) 應該,該
You don't look well.You ought to go to see the doctor.
3.(表示猜測、期望) 總應該,理應
It ought to be a fine day tomorrow morning.
4.“ought to + have + 過去分詞”表示過去應做某事而實際未做
You ought to have told me that (but you didn't).
這時ought to和should可以互換使用.
二、ought to的否定式和疑問式
1.ought to的否定形式是ought后直接加not構(gòu)成,其否定形式可縮寫為oughtn't.
One ought not (oughtn't) to cross the street against the red light.
2.ought to的疑問式是將ought提到句首構(gòu)成.
—Ought we to do it at once?—Yes,you ought to.
在反意疑問句里,下面兩種形式都可以：
He ought to be here now,shouldn't (oughtn't) he?