Réponse :
If she had known she wouldn't have taken the plane
If she had known she would have married him
If she had known She wouldn't have opened the door
If she had know she wouldn't have read that book.
Explications :
si condition au pastperfect (If she had known : si elle avait du) la conséquence est au conditionnel passé (would (not) have + participe passé, ex she wouldn't have read that book : elle n'aurait pas lu ce livre.)