Photo taken on Sept 28, 2016 shows Sang Lei helping students cross a river to Dimaluo village, a remote village in Nujiang Lisu autonomous prefecture of Southwest China's Yunnan province. Sang Lei, a college graduate majored in computer education, has been as a voluntary teacher of Pengdang Primary School since 2007. In nearly ten years of teaching, he tried his best to provide better learning environment for his pupils. Since 2006, more than 500,000 young people in China like Sang Lei have gone to central and western China to offer educational support to the country's remote rural regions. [Photo /Xinhua]