Complex sentence: Graham served as a bomber pilot in 166 Squadron from 1940, flying Lancashires over Germany, and made Flight Lieutenant in the RAF during World War II and was awarded the Distinguished Flying Cross in December 1944 for bravery.
Split into simpler sentences: Graham served as a bomber pilot in the RAF during World War II. He was assigned to the 166 Squadron from 1940, flying Lancasters over Germany, and made Flight Lieutenant. He was awarded the Distinguished Flying Cross in December 1944 for bravery.