Troisième conditionnel (if + had done)

Le troisième conditionnel imagine un passé différent : des choses qui ne sont pas arrivées et leurs conséquences. Il sert souvent à exprimer des regrets. Forme : if + past perfect, would have + participe passé (si j’avais…, j’aurais…).

Remarques

• could have / might have pour la possibilité : If you’d asked, I could have helped.
• À l’oral : I’d have = I would have ; If I’d known = If I had known.

Exemples

• If I had studied more, I would have passed the exam.Si j’avais plus travaillé, j’aurais réussi l’examen.
• She wouldn’t have got the job if she hadn’t applied early.Elle n’aurait pas eu le poste si elle n’avait pas postulé tôt.
• What would you have done if you had been there?Qu’est-ce que tu aurais fait si tu avais été là ?
• If you had told me, I could have helped.Si tu me l’avais dit, j’aurais pu t’aider.
• If it hadn’t rained, we would have gone hiking.S’il n’avait pas plu, nous serions allés faire une randonnée.

Erreurs courantes

• ✗ If I had known, I will have come.✓ If I had known, I would have come.Dans la proposition principale du troisième conditionnel on emploie would have et non will have.
• ✗ If I knew, I would have come.✓ If I had known, I would have come.Pour un passé irréel la partie avec if prend le past perfect et non le past simple.
• ✗ If I had known, I would come.✓ If I had known, I would have come.La conséquence dans le passé demande would have + participe passé.
• ✗ If she had studied, she would passed.✓ If she had studied, she would have passed.Après would il faut have + participe passé, et non le participe seul.
• ✗ If I had went there, I would have seen it.✓ If I had gone there, I would have seen it.Après had on emploie le participe gone et non went.