Answer:
10 key Second World War dates you need to know
7 July 1937: Clash near the Marco Polo Bridge, close to Beijing. ...
10 May 1940: Germans launch offensive in the West. ...
12 August 1940: Battle of Britain begins. ...
22 June 1941: Launching of Operation Barbarossa. ...
7 December 1941: Attack on Pearl Harbor. ...
4 June 1942: Battle of Midway.
And some causes
1939: Hitler invades Poland. Hitler's invasion of Poland on 1st September 1939 marked the beginning of WW2 in Europe.
1940 (1): Rationing. ...
1940 (2): Blitzkrieg. ...
1940 (3): Churchill Becomes Prime Minister. ...
1940 (4): Evacuation of Dunkirk. ...
1940 (5): Battle of Britain. ...
1941 (1): Operation Barbarossa. ...
1941 (2): The Blitz.