Third conditional (If I had known ...)

Third conditional (If I had known ...) means “Third conditional: imagining a past situation that did not happen — if + past perfect, would have + past participle”. The third conditional talks about a past that we cannot change. Formation: if + past perfect, would have + past participle

Third conditional: imagining a past situation that did not happen — if + past perfect, would have + past participle

B2

Formation

if + past perfect, would have + past participle

Explanation

The third conditional talks about a past that we cannot change. The if-clause uses the past perfect (had + past participle) and the main clause uses would have + past participle: If I had left earlier, I would have caught the bus. It often expresses regret or criticism about something that already happened. Instead of would, you can use could have or might have to show ability or possibility.

Examples

If I had studied harder, I would have passed the exam.
If we had known about the traffic, we would have left earlier.

Note

Never use would have in the if-clause: say If I had known, not If I would have known.

FAQ

Third conditional (If I had known ...) — what does it mean and how is it used?

Third conditional: imagining a past situation that did not happen — if + past perfect, would have + past participle. The third conditional talks about a past that we cannot change. The if-clause uses the past perfect (had + past participle) and the main clause uses would have + past participle: If I had left earlier, I would have caught the bus. It often expresses regret or criticism about something that already happened. Instead of would, you can use could have or might have to show ability or possibility.

Third conditional (If I had known ...) — how do you form it?

if + past perfect, would have + past participle

Third conditional (If I had known ...) — any usage notes?

Never use would have in the if-clause: say If I had known, not If I would have known.

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