Children and their teacher play a sleeping game at a kindergarten in Weinan City, northwest China's Shaanxi Province, March 21, 2017. Tuesday marks the World Sleep Day.(Xinhua/Cui Zhengbo)
Children and their teacher play a sleeping game at a kindergarten in Weinan City, northwest China's Shaanxi Province, March 21, 2017. Tuesday marks the World Sleep Day.(Xinhua/Cui Zhengbo)