BTW, I wish history textbooks and teachers in the USA would stress the fact that World War II had already been raging for two years and three months prior to the US entering the conflict. It is pretty well acknowledged that the war officially began on September 1st, 1939, when German invaded Poland. The Japanese attacked Pearl Harbor on December 7th, 1941. The US declared war on Japan the next day. Germany and Italy, allies of Japan, declared war on the US on September 11th, 1941. The US then declared war on them that same day.
The British Empire kept the fight against Nazi Germany alive after the miracle at Dunkirk, after the Fall of France, through the Battle of Britain, through the Blitz. They even won a morale-boosting decisive victory against Germany's Panzer Army Africa at the Second Battle of El Alamein.
The US entry in the war was a decisive event, but the US didn't win the war all by itself.