ought to
should
ought toYou use should or ought to to say that you expect something to happen.
You use should or ought to with have and an -ed participle to say that you expect something to have happened already.
You also use should or ought to with have and an -ed participle to say that something was expected to happen, but did not happen.
Be Careful!
You must use have and an -ed participle in sentences like these. Don't say, for example, 'The project ought to finish by now'.
You use should or ought to to say that something is morally right.
You can say you should or you ought to when you are giving someone advice.
Should and ought to have the negative forms should not and ought not to.
The not is not usually pronounced in full. When you write down what someone says, you write shouldn't or oughtn't to.
When you make a negative statement with ought in American English, you can omit to: