Complex sentence: Lu started working as the official photographer for the Chinese government in 1950, thereby assigned to take pictures in Zhongnanhai of the main Chinese leaders of that time including Chairman Mao Zedong, Premier Zhou Enlai and President Liu Shaoqi.
Split into simpler sentences: Lu started working as the official photographer for the Chinese government in 1950. He was assigned to take pictures in Zhongnanhai of the main Chinese leaders of that time including Chairman Mao Zedong, Premier Zhou Enlai and President Liu Shaoqi.