Duolingo Guidebook

Si tu avais écouté, tu aurais déjà compris.
If you had listened, you would have already understood.

Si on le lui avait acheté, il l'aurait déjà cassé.
If we had bought it for him, he would have already broken it.

S'ils n'avaient pas oublié la clé, ils seraient entrés.
If they hadn't forgotten the key, they would have gone in.

Si vous étiez venus, vous auriez eu des macarons.
If you had come, you would have had some macarons.

Si vous aviez répondu, on aurait su où vous étiez.
If you had responded, we would have known where you were.

S'il s'était levé tôt, il serait arrivé à l'heure.
If he had gotten up early, he would have arrived on time.

To talk about things you would have done, it's like the passé composé but avoir or être are in the conditional form.

Si tu avais demandé, j’aurais raconté mon histoire.
If you had asked, I would have told my story.

Si vous aviez voulu, nous aurions acheté des fleurs.
If you had wanted, we would have bought flowers.

Verbs of motion or change of state use être instead of avoir in phrases like I would have gone.

Si elle avait su, elle serait arrivée plus tôt.
If she had known, she would have arrived earlier.

S’il avaient appelé, nous serions allés avec lui.
If he had called, she would have gone with him.