Complex sentence: During the 1960s and 70s, Chavalit served in the Communist insurgency suppression campaign in the jungles of Thailand, and prepared Thai soldiers for their operations in the Vietnam War.
Split into simpler sentences: During the 1960s and 70s, Chavalit served in the Communist insurgency suppression campaign in the jungles of Thailand. Moreover he prepared Thai soldiers for their operations in the Vietnam War.