課本中不會教你的[O]518　ought to和should

518　ought to和should

◎ ought to和should意為“應該，應當，總應該”，為情態(tài)動詞，沒有人稱、時態(tài)變化。

① ought to do sth.可表示責任或義務，指道義上應該做的事?？杀硎粳F(xiàn)在、一般將來或過去將來。

We ought to pay what we own. 欠債還錢，理所應當。

You ought to respect the old. 你們應該尊敬老人。

There ought not to be much noise in a hospital. 醫(yī)院里不該喧鬧。

You ought to take part in the meeting tomorrow. 你應該參加明天的會議。

② ought to可表示“應有的結果”或“當然的事”。

You've been roommates for four years，so you ought to know her well. 你們同住一室已有四年了，應該很了解她。

If he started at seven，he ought to be here now. 要是他七點鐘出發(fā)，這會兒該到了。

He is from Japan；he ought to know Japanese. 他是從日本來的，當然懂日語。

③ ought to在口語中可表示“愿望”。

You ought to read the book twice. 這本書你要看兩遍才好。

We ought to see the flower show. 我們去看看花展才好。

④ ought to在語氣上比 must 弱，但比 should 強。比較：

You ought to finish the task today. 你應該今天完成這項任務。

You should finish the task today. 你該今天完成這項任務才是。

You must finish the task today. 你必須今天完成這項任務。

⑤ ought to have done sth.表示“應該做某事而未做”，含有責備、遺憾等意。

You ought to have returned the book last week. 這本書你上周就該還的。

Why did you not tell me the truth？You ought to have done so. 你為什么不告訴我實話呢？說了實話就好了。

The child ought not to have been allowed to go alone the other day. 那天，本不該讓這孩子一人去的。

⑥ ought to的否定式和疑問式。

A：Ought I to go there？我應該去那里嗎？

B：Yes，you ought. 是的，應該。

B：No，you ought not. 不，不應該。

It ought to rain after this long drought，oughtn't/shouldn't it？旱了這么久，也該下雨了，不是嗎？

Oughtn't he to give them more care？難道他不該給他們更多的幫助嗎？

⑦ should指主觀上感到有責任或義務去做某事。should+完成式表示過去的動作，常含有責備、遺憾的意味，表示“本應該，應該已經”，而實際上卻沒有。

She should have shut the door against him. 她本應該將他拒之門外的。（但沒有這樣做）