Complex sentence: Large-scale bombing of Germany escalated in 1944 as the Nazis retreated from Eastern and Southern Europe and following an Allied invasion of France, Germany was conquered by the Soviets from the east and the other Allied powers from the west and surrendered within a year.
Split into simpler sentences: Large-scale bombing of Germany escalated in 1944, and the Nazis retreated from Eastern and Southern Europe. Following the Allied invasion of France, Germany was conquered by the Soviets from the east and the other Allied powers from the west and surrendered within a year.