Zuo Zong (L), a volunteer teacher from Fudan University, guides a student at the radio station of the campus in Wangmin Middle School in Xiji County, northwest China's Ningxia Hui Autonomous Region, April 22, 2019. A volunteer teaching team made of postgraduates from Fudan University has been consecutively offering teaching service in Xiji County since 1999. A total of 224 teachers have offered teaching service in 9 local middle schools and helped to promote education in Xiji County. (Xinhua/Lu Ying)