Complex sentence: At first, tenacious KPA defense halted the Marines who responded with artillery, raking Cloverleaf Hill heavy indirect fire forced the North Koreans out of their positions before the Marines and Task Force Hill eventually overwhelmed them, one hill at a time.
Split into simpler sentences: At first, tenacious KPA defense halted the Marines who responded with artillery, raking Cloverleaf Hill. Heavy indirect fire forced the North Koreans out of their positions before the Marines and Task Force Hill eventually overwhelmed them, one hill at a time.