Complex sentence: David was commissioned as a second lieutenant into the Royal Corps of Signals on 16 August 1939 and was awarded the Military Cross for his work during the Dunkirk evacuation of World War 2.
Split into simpler sentences: David was commissioned as a second lieutenant into the Royal Corps of Signals on 16 August 1939. He was awarded the Military Cross for his work during the Dunkirk evacuation of World War 2.