Réponse :
a. If you had listened to your friends, you wouldn't have been in trouble.
b. Paul wouldn't have bought that video game if he had known it was so bad.
c. She would have visited the Rockefeller Centre if she had had money.
d. What would you have done if you had found her purse?
e. If my brother hadn't met Professor Smith, he wouldn't have
become a famous lawyer.
Explications :
Si condition au pastperfect (had+(not) + PP) la conséquence est au conditionnel passé (would+(not)+have+ PP)
PP : participe passé : si verbe régulier =BV+ED
si verbe irrégulier = 3ème colonne de la liste (write par exemple son PP est written)