During world war ll what happened between the communists and nationalists in china?

As a matter of fact, prior to World War II and because of the Japanese invasion of China begun in 1937, Nationalists led by Generalissimo Chiang Kai shek and Communists lead by Mao Zedong agreed to cease hostilities between them in order to fight the common enemy of their country, the Japanese Imperial Army. Both groups started receiving aid, weapons, military equipment  and supplies from the U.S. in limited amounts at first and these increased as the U.S. entered the war due to the attack to Pearl Harbor by the Japanese on December 7, 1941. Shortly after the end of the war and the withdrawal of all Japanese military personnel from China in 1945 , both groups resumed hostilities. Three years later the Communists would decisively defeat Nationalist forces and forced them to flee to the island of Formosa, today known as Taiwan.