B2 Upper-intermediate Conditionals, wish and modal perfect
Modal perfect
Lesson goal. After this lesson you can deduce and evaluate the past: it surely did, it surely did not, it may have, and it should have.
When to use it
- Confident deduction: The ground is wet — it must have rained.
- Ruling out: He can't have cheated — he's brilliant.
- Possibility: She might have missed the bus.
- Mild reproach or regret: You should have told me.
Form
| Form | Example |
|---|---|
| must have + V3 | It must have rained. |
| can't have + V3 | He can't have seen me. |
| might / may / could have + V3 | She might have left. |
| should have + V3 | You should have called. |
| shouldn't have + V3 | I shouldn't have eaten that. |
Step by step
- Check that you are talking about a past event.
- Choose the modal for your meaning: certainty, possibility, or reproach.
- Add have and then the V3 — the part learners drop.
- Check: every past deduction has all three parts, modal + have + V3.
Present and past
| Present | Past |
|---|---|
| He must be at home. | He must have been at home. |
| She can't be serious. | She can't have been serious. |
| They might be late. | They might have been late. |
Examples
The ground is wet. It must have rained last night.
You should have called me. I was waiting all evening.
She can't have read the email — she never checks her inbox.
He isn't here. He might have missed the bus.
I shouldn't have eaten so much.
They look tired — they must have worked all night.
Common mistakes
He must worked late last night. → He must have worked late last night.
have is missing. Modals cannot take a past form themselves, so they borrow have + V3.
You should told me earlier. → You should have told me earlier.
The same error: have is missing.
He mustn't have gone out. → He can't have gone out.
Negative past deduction uses can't have, not mustn't have.
Memory tip
Modals have no past form of their own. To reach the past they borrow have + V3 — remember that and you will never drop the have.
Summary
- must have surely did · can't have surely did not · might have may have.
- should have ought to have · shouldn't have ought not to have.
- Always three parts: modal + have + V3.
Practise this lesson
Do exercises with an explanation for every question, take mini tests and track your progress on GrammUp.