Doesn't the second sentence convey the idea of something that should have been done but hasn't? Yes, it does convey that idea...if the teacher knows that something that should have been done, hasn't been done. There are two variations of 'should' and 'ought to' when using *reported speech. HAVE TO and MUST can express necessity. HAD TO is the past form of 'must' and 'have to' when they express necessity. "You have to work harder, John," said the teacher. "You must work harder, John," said the teacher. The teacher told John that he had to work harder. OUGHT TO and SHOULD can express advisability. * "You ought to work harder, John," said the teacher. 1)The teacher told John that he ought to work harder. ----In this case the teacher does not know if John followed the advice to work harder. 2)The teacher told John that he ought to have worked harder. ----In this case the teacher knows that John did not follow the advice. "You should work harder, John," said the teacher. 1) The teacher told John that he should work harder ---In this case the teacher does not know if John followed the advice. 2) The teacher told John that he should have worked harder. ---In this case the teacher knows that John did not follow the advice thanks to learner for the clarification!

I disagree with Denis on the second point (should and ought to): ''You should work harder, John," said the teacher. The teacher told John that he should work harder. (shoud have worked : INCORRECT) The teacher told John that he ought to work hard. (ought to have worked: INCORRECT) Advise expressions with must, should and ought to are usually reported using advise / urge: "You have to / must work harder, John," said the teacher The teacher told John that he had to work harder. = The teacher urged John to work hard. "You should work harder, John." The teacher advised John to work harder. should / ought to: advice should have / ought to have + past participle: Regret / Reproach = express the idea that something was desirable or needed, but did not take place

i don't think the thing should be done is finished , just a kind of thing he have to do in his heart and he should keep on doing 嘿嘿。。。

I can be mistaken, but I think I make this sentence in this way - the teacher told John that he ought to work harder, or should to work harder. (it seems that with the infinitif would be more correct) Bye,

in this case , "The teacher told John that the ought to have worked harder. " i think it mean should but in the tense of something that should be done but wasn't... to me hasn't means you still have a chance to do something. but with that ought to you don't have another chance to fix it do i make sense?