Complex sentence: Holt made her film debut using the stage name "Jacqueline Holt" in a 1941 western starring Hopalong Cassidy and went on to make 47 films during the 1940s.
Split into simpler sentences: Holt made her film debut using the stage name "Jacqueline Holt" in a 1941 western starring Hopalong Cassidy. She went on to make 47 films during the 1940s.