“Ought” is a modal verb, and it has the same meaning as “should”. It can be used to express a moral obligation or desirability, and probability.
First, expressing an obligation and something that is desirable:
- I ought to do it (debería hacerlo).
- He ought to have known it (debía saberlo).
- You ought to be grateful (deberías estar agradecido).
- Mr. Podemos ought to have apologised to Mr. Sanchez (…debería haberle disculpado a…).
- Mr. Corbyn ought not to have said that (…no debería haber dicho eso).
- The students ought to be there by now (… y deberían de haber llegado).
- Mr. Sanchez ought to win the election (…debería ganar…).
Please note that “ought” requires the preposition “to” to follow, whereas “should” does not have that requirement.