In this file photo taken on Dec. 18, 2007, students play a classic marble game at Changjianglu Primary School in Nanjing, east China's Jiangsu Province. As China celebrates the International Children's Day, there arises the occasion for grown-ups to think back over the joys of childhood. With the evolution of technology and lifestyle, children are exposed to a wider range of entertainment. Nevertheless, joy would remain a childhood motif no matter how its forms change with time. (Xinhua/Sun Can)