Pupils demonstrate smiley cards to greet the upcoming World Smile Day at a primary school in Qinhuangdao, north China's Hebei Province, May 7, 2019. World Smile Day is celebrated on May 8 every year. (Xinhua/Cao Jianxiong)
A girl demonstrates a handmade smiley card to greet the upcoming World Smile Day at a kindergarten in Zhenjiang, east China's Jiangsu Province, May 7, 2019. World Smile Day is celebrated on May 8 every year. (Xinhua/Shi Yucheng)
Children demonstrate smiley cards to greet the upcoming World Smile Day at a kindergarten in Zigui County, central China's Hubei Province, May 7, 2019. World Smile Day is celebrated on May 8 every year. (Xinhua/Wang Huifu)
Pupils demonstrate smiley cards to greet the upcoming World Smile Day at a primary school in Handan, north China's Hebei Province, May 7, 2019. World Smile Day is celebrated on May 8 every year. (Xinhua/Hao Qunying)