Réponse :
Bonsoir,
a) He had been in Los Angeles for two years when he finally got a small part in Dallas : "for two years"
b) When he won his Golden Globe, he had already played in more than 15 films and had attracted broad public attention. : "When he won his Golden Globe"
c) Even before he started his acting career, he had won a Grammy Award for best rapper : "before he started his acting career"