Complex sentence: Alexey Borisovich Miller (born 31 January 1962) is Deputy Chairman of the Board of Directors and Chairman of the Management Committee (CEO) of Russian energy company Gazprom, Russia's largest company and the world's biggest public energy supplier.
Split into simpler sentences: Alexey Borisovich Miller (born 31 January 1962) is a Russian business administrator. Miller is the Deputy Chairman of the Board of Directors and the Chairman of the Management Committee (CEO) of Russian energy company Gazprom, Russia's largest company and the world's biggest public energy supplier.