I would have done
That's what I would have done.
I would have done better than him.
Si j'étais toi, j'aurais fait la même chose dans une situation aussi difficile.
If I were you, I would have done the same thing in such a difficult situation.
J'aurais fait exactement ce que tu as fait.
I would have done exactly what you did.
Je ne sais pas ce que j'aurais fait sans toi.
I don't know what I would have done without you.
Parce que c'est ce que j'aurais fait.
Because that's what I would have done.