Complex sentence: Except for patrol skirmishes, all of the major combat to expand the beachhead occurred in the Marine sector, with the following battles taking place during this time: the Battle for Piva Trail, the Battle of the Coconut Grove and the Battle of Piva Forks.
Split into simpler sentences: Except for patrol skirmishes, all of the combat to expand the beachhead occurred in the Marine sector. Operations resulted in the Battle for Piva Trail, Battle of the Coconut Grove, Battle of Piva Forks.