Complex sentence: He continued to impress as the season went on, and in San Marino Hill took the lead at the start, though he was passed by Prost and Senna and ultimately retired with brake failure.
Split into simpler sentences: He continued to impress as the season went on. In San Marino, Hill again impressed by taking the lead at the start, though he was passed by Prost and Senna and ultimately retired with brake failure.