Complex sentence: Hillgrove High School was built on 98 acres that was donated to Young Harris College and sold to the Cobb County School District by Dr. Harry Hill and Mrs. Harriet Hargrove Hill.
Split into simpler sentences: Hillgrove High School was built on 98 acres. The Land was donated to Young Harris College and sold to the Cobb County School District by Dr. Harry Hill and Mrs. Harriet Hargrove Hill.