Both imagine something unreal. The second conditional imagines now or the future: If I had time, I would help. The third imagines the past: If I had had time, I would have helped.
Same situation, two choices. Pick an example.
If I had time, I'd help you.
The imagined path runs above the present: things aren't this way now.
If I had had time, I'd have helped you.
The imagined path leaves in the past and ends there: it didn't happen, and it's too late to change.
| Rule | Second conditional | Third conditional |
|---|---|---|
| Form | if + Past Simple, would + base verb | if + Past Perfect, would have + past participle |
| Time | Now or the future | The past |
| Can it still change? | In theory, yes | No, it's too late |
| Example | If I were rich, I'd travel. | If I had been rich, I'd have travelled. |
If I _____ his address, I'd send him a card. But I don't.
Paste an email or an essay. Clarigram marks the mistakes you actually make, shows the rule behind each one as a picture, and builds your practice from them.
Yes. It's the Past Perfect of have: If I had had time, I would have helped. In speech it's often If I'd had time.
Use a mixed conditional: If I had taken the job, I would be rich now.