We usually say "ought to" not "ought". (Although more often we say "should"). I wonder when I can say "ought" without "to".
Some examples:
- 1: Ought I to tell him?
- 2: Yes, you ought to
- 3: I don't learn as often as I ought to
- 4: ‘Ought I to write to say thank you?’ ‘Yes, I think you ought (to).’ (From Oxford Learner's Dictionary)
- 5: We ought not to have ordered so much food
Can I omit "to" after "ought". Why?