The three ``Left'' lines comprise the error of ``Left'' putschism represented by Qu Qiubai during the period from November 1927 to April 1928, the error of ``Left'' adventurism represented by Li Lisan from June to September 1930, and the error of ``Left'' adventurism represented by Wang Ming during the period between January 1931 and the Zunyi Meeting of the Political Bureau held in January 1935.