Complex sentence: Surviving documents said nothing about infiltrators at No Gun Ri, even though they would have been the 7th Cavalry's first enemy killed-in-action in Korea, and only three of 52 battalion soldiers interviewed said their unit was returning infiltrators' fire.
Split into simpler sentences: Surviving documents said nothing about infiltrators at No Gun Ri, even though they would have been the 7th Cavalry's first enemy killed-in-action in Korea. Only three of 52 battalion soldiers interviewed said their unit was returning infiltrators' fire.