2019小學(xué)英語(yǔ)語(yǔ)法專(zhuān)題：如何表達(dá)本來(lái)該做某事?

　　should have done

　　should have + 動(dòng)詞的完成式表示本應(yīng)該做而實(shí)際上沒(méi)有做，它的否定形式表示某種行為本不該發(fā)生但卻發(fā)生了。有責(zé)備的意味。

　　You should have started earlier， but you didnt.

　　你本應(yīng)該早點(diǎn)兒出發(fā)，但是你沒(méi)有。

　　You should have washed the wound.

　　你應(yīng)該已經(jīng)洗好了傷口。

　　She shouldnt have taken away my dictionary， for I wanted to use it.

　　她本不應(yīng)該拿走我的詞典，因?yàn)槲乙�用它�?br />
　　You shouldnt have been so rude to him.

　　你本不應(yīng)該對(duì)他那么粗魯。

　　注：should have + 完成式雖然可以表猜測(cè)，但因?yàn)闀?huì)造成歧義，應(yīng)少用。

　　ought to have done

　　1、ought to have + 動(dòng)詞的完成式表示過(guò)去應(yīng)做某事而實(shí)際未做，它的否定形式表示本不應(yīng)該做某事卻做了(用法和should相同)。

　　You ought to have helped him， but you didnt.

　　你本應(yīng)該幫助他但你沒(méi)有。

　　You ought to have studied harder.

　　你本應(yīng)該更努力學(xué)習(xí)的。

　　He ought not to have stopped his work halfway.

　　他本不應(yīng)該做這項(xiàng)工作時(shí)半途而廢。

　　He oughtnt to have done that.

　　他本來(lái)就不該做那件事。

　　2、ought to have + 動(dòng)詞的完成式還可以用來(lái)表猜測(cè)。

　　They ought to have arrived by now.

　　現(xiàn)在他們想必已經(jīng)到達(dá)。