Complex sentence: William Marshall Roark (October 23 1943, Sioux City, Iowa-April 7 1965) was appointed to the U.S. Naval Academy in 1956, he graduated and was commissioned ensign on 8 June 1960 and advanced to the rank of lieutenant, 1 June 1964.
Split into simpler sentences: William Marshall Roark (October 23 1943, Sioux City, Iowa-April 7 1965). Appointed to the U.S. Naval Academy in 1956, he graduated and was commissioned ensign on 8 June 1960 and advanced to the rank of lieutenant, 1 June 1964.