Identify some of the ways Germany and Japan test the Allied Powers during the 1930s. How did the Allied nations respond to Hitler's actions?

Germany were sinking the allied powers boats, and England sent a letter to Germany telling them to basically tell them to stop. They continued, and we dropped on Normandy, or D-Day. Japan was doing some shady stuff with Korea, so we ceased trade with Japan, and in response Japan got mad and launched pearl harbor.