Complex sentence: Chubar became a Marxist revolutionary early in life and joined the Bolshevik faction of the Russian Social Democratic Labor Party in 1907, rising through the ranks during the Russian Civil War and becoming a member of the Central Committee of the Soviet Communist Party in 1921.
Split into simpler sentences: Chubar became a Marxist revolutionary early in life and joined the Bolshevik faction of the Russian Social Democratic Labor Party in 1907. He rose through the ranks during the Russian Civil War and become a member of the Central Committee of the Soviet Communist Party in 1921.