Ought to have plus the past participle is a formal, slightly old-fashioned synonym of should have, as in the board ought to have consulted shareholders. The obligatory to is never dropped, including in the negative, ought not to have, as in she ought not to have criticized him in public.
Grammar Rule
Ought to have + past participle is a formal, slightly old-fashioned synonym of should have + past participle. The crucial structural difference is the obligatory to: ought is always followed by to plus have plus past participle, never a bare infinitive. The negative is ought not to have — never drop to in either form.
Ought To + Perfect Infinitive: Rules and Examples
| Form | Rule | Example |
|---|---|---|
| Ought to have + past participle | formal synonym of should have; keep to | The board ought to have consulted shareholders. |
| Negative: ought not to have | never drop to | She ought not to have criticized him in public. |
| Common error | dropping to in affirmative or negative | ought have / ought not have (incorrect) |
Remember: Ought to have plus past participle is the formal twin of should have — always keep to, including in the negative.
Practice Test
Instructions
Answer each question in the test below using ought to have correctly. You will get a new random set of questions every time you retake the test, plus a downloadable results summary with your name and score at the end.
C1-39 Ought to + Perfect Infinitive
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Frequently Asked Questions
What does ought to have plus the past participle mean?
A formal synonym of should have, as in the board ought to have consulted shareholders.
What is the negative form of ought to have?
Ought not to have, as in she ought not to have criticized him in public.
Can to be dropped after ought?
No, to must always be kept, in both the affirmative and negative.
Is ought to have more formal than should have?
Yes, it is a slightly old-fashioned, more formal synonym.