- Ought is a ‘modal auxiliary verb’. The third person singular has no -s.
She ought to understand.
We usually make questions and negatives without do.
Ought we to go now? (NOT Do we ought . . . ?)
It oughtn’t to rain today.
After ought, we use the infinitive with to. (This makes ought different from other modal auxiliary verbs.)
You ought to see a dentist.
We can use ought to advise people (including ourselves) to do things; to tell people that they have a duty to do things; to ask about our duty. The meaning is similar to the meaning of should ; not so strong as must .
- What time ought I to arrive?
I really ought to phone Mother.
People ought not to drive like that.
We can use ought to say that something is probable (because it is logical or normal).
- Henry ought to be here soon — he left home at six.
‘We’re spending the winter in Miami. ‘ ‘That ought to be nice.’
We can use ought + perfect infinitive to talk about the past. This structure is used to talk about things which did not happen, or which may or may not have happened .
- [ought to + have + past participle]
I ought to have phoned Ed this morning, but I forgot.
Ten o’clock: she ought to have arrived at her office by now.