sentences:  He then moved to the United States, where he obtained a master's degree in Economics at Columbia University in 1925.On his return to China he joined the Kuomintang (KMT) and was named head of the Department of Peasants and Workers under Liao Zhongkai, and was considered a member of the KMT leftist clique together with Wang Jingwei, with whom he developed a close political and personal relationship.Although he played a significant role in Chiang Kai-shek’s Northern Expedition, he—along with Wang Jingwei—strongly opposed Chiang as Chiang began to exercise dictatorial power.