Complex sentence: Davis Filfred served in the United States Marine Corps and achieved the Rank of Sgt. or pay-grade E- 5 during his enlistedment, in the Operation Desert Shield/Desert Storm.
Split into simpler sentences: Davis Filfred served in the United States Marine Corps and achieved the Rank of Sgt. or pay-grade E- 5. During his enlistedment, in the Operation Desert Shield/Desert Storm.