Complex sentence: The show, which co-starred former silent film actor Charles Farrell as her father, was originally a summer replacement for "I Love Lucy" on CBS, but ran for 126 episodes on NBC and CBS.
Split into simpler sentences: The show, which co-starred former silent film actor Charles Farrell as her father, was originally a summer replacement for "I Love Lucy" on CBS. The popular show ran for 126 episodes on NBC and CBS.