Complex sentence: He was promoted to Major-General in command of Administration for Southern Command, 1938-1939 and was appointed the Quartermaster-General on mobilisation of the British Expeditionary Force in France and Belgium, 1939-1940, until the evacuation from Dunkirk.
Split into simpler sentences: He was promoted to Major-General in command of Administration for Southern Command 1938-1939. During World War II 1939-1945 he had several positions including Quartermaster General to the British Expeditionary Force in France and Belgium 1939-1940 until the evacuation from Dunkirk.