Complex sentence: World War II (WWII or WW2), also known as the Second World War, was a global war that lasted from 1939 to 1945, though some related conflicts in Asia began before 1939.
Split into simpler sentences: World War II (WWII or WW2), also known as the Second World War, was a global war. It lasted from 1939 to 1945, though some related conflicts in Asia began before 1939.