Complex sentence: In 1967 U.S commanders in the battlefield were under pressure to engage the Viet Cong and destroy them in decisive battles, under such pressure many U.S officers were dismissed as a result of their failure to engage the Viet Cong in large operations.
Split into simpler sentences: In 1967 U.S. commanders in the battlefield were under pressure to engage the Viet Cong and destroy them in decisive battles. Under such pressure, many U.S. officers were dismissed as a result of their failure to engage the Viet Cong in large operations.