四、语法详解

1.ought to

（1）表义务，意为"应该"（在责任、义务上等该做），口气比should稍重。

You are his father.You ought to take care of him.

你是他父亲，应当管他。

You ought not to smoke so much.

你不应该抽这么多烟。

（2）含有ought to的反意疑问句，陈述部分是肯定的，疑问部分用shouldn't/oughtn't +主语。

He ought to know what to do, oughtn't he?/shouldn't he?

活学巧用

1.1）单项选择

-There is a lot of smoke coming out of the teaching-building there.

-Really?It _________ be a fire,most probably.

A.can B.ought to C.have to D.must

答案:B

2）完成句子

Zhou Lan ought to pass the National College Entrance Examinations,_________she?

答案:oughtn't/shouldn't