Complex sentence: Clooney's first role was as an extra in the television mini-series "Centennial" in 1978, which was based on the novel by James A. Michener, and was partially filmed in Clooney's hometown of Augusta, Kentucky.
Split into simpler sentences: Clooney's first role was as an extra in the TV series "Centennial" in 1978. The series was based on the novel of the same name by James A. Michener, and was partially filmed in Clooney's hometown of Augusta, Kentucky.