Complex sentence: When Duke was six, her mother threw her father out; when she was eight, her mother turned her care over to John and Ethel Ross, who later became her managers; they recognized her talent and promoted her as a child actress.
Split into simpler sentences: When Duke was six, her mother threw her father out; when she was eight, her mother turned Duke's care over to John and Ethel Ross, who later became her managers. The Rosses recognized her talent and promoted her as a child actress.