Complex sentence: The following year she took on the role of Susan Ross in 11 episodes of Seinfeld's fourth season, 16 episodes of the seventh season and one episode of the ninth season (via flashback in the' backward' episode).
Split into simpler sentences: The following year she took on the role of Susan Ross. She played Ross in 11 episodes of Seinfeld's fourth season, 16 episodes of Seinfeld's seventh season, and one episode of Seinfeld's ninth season (via flashback in the' backward' episode).