Students manipulate a robotic arm at Nanyingzi primary school in Chengde City, north China's Hebei Province, Dec. 20, 2018. Shuangqiao District of Chengde City has witnessed an increasing investment in education as 36 school building projects have been completed to make the enrollment numbers increase by 5,298 in recent three years. Also extra-curriculum classes are provided at various schools. (Xinhua/Niu Xiaolei)