Complex sentence: The next year, he became a member of the Communist party, served diligently in junior command positions, and starting in 1926, he spent the next decade alternating service with studies in the elite Frunze Military Academy and General Staff Academy.
Split into simpler sentences: The next year, he became a member of the Communist party, and served diligently in junior command positions. Starting in 1926, he spent the next decade alternating service with studies in the elite Frunze Military Academy and the General Staff Academy.