Answer:
Although the war began with Nazi Germany's attack on Poland in September 1939, the United States did not enter the war until after the Japanese bombed the American fleet in Pearl Harbor, Hawaii, on December 7, 1941.
Step-by-step explanation:
Reasons for the United States Entering world war2
1•The Japanese Attack on Pearl Harbor.
2•Japanese Control of China and Asia.
3•Germany's Aggression and Unrestricted submarine Warfare Sinking U.S. Ships.
4•Fear of German Expansion and invasion