Complex sentence: The head cheerleader, Jeff's girlfriend, and the only child of the county commissioner, Harold Cline and his wife Liz, she is in love with Mark, yet he is uninterested in her.
Split into simpler sentences: The head cheerleader, Jeff's girlfriend, and the only child of the county commissioner, Harold Cline and his wife Liz. She is in love with Mark, yet he is uninterested in her.