Complex sentence: Although the U.S. denied that it had combat soldiers in South Vietnam, U.S. soldiers routinely participated in combat operations against the Viet Cong and the number of U.S. soldiers in South Vietnam rose to more than 16,000 by year's end with 122 combat deaths.
Split into simpler sentences: Although the U.S. denied that it had combat soldiers in South Vietnam, U.S. soldiers routinely participated in combat operations against the Viet Cong. The number of U.S. soldiers in South Vietnam rose to more than 16,000 by year's end with 122 combat deaths.