Complex sentence: Rosenberg was President of the Saul Zaentz Production Company and Fantasy Films in Berkeley, California for ten years, during wbich time the company released "One Flew Over the Cuckoo's Nest", "Amadeus", and "The English Patient".
Split into simpler sentences: Rosenberg was President of the Saul Zaentz Production Company and Fantasy Films in Berkeley, California for ten years. He was involved in "One Flew Over the Cuckoo's Nest", "Amadeus", and "The English Patient".