1940 - Axis gain momentum in WWII (video)
The link address is: https://www.khanacademy.org/humanities/ap-us-history/period-7/apush-us-wwii/v/1940-axis-gains-momentum-in-world-war-ii
The link address is: https://www.khanacademy.org/humanities/ap-us-history/period-7/apush-us-wwii/v/1940-axis-gains-momentum-in-world-war-ii