Children practice dancing skills at a training center during their summer vacation in Nanhe County, north China's Hebei Province, July 15, 2018. (Xinhua/Zhu Xudong)

Children learn opera performing skills at a training center during their summer vacation in Nanhe County, north China's Hebei Province, July 15, 2018. (Xinhua/Zhu Xudong)

Children learn tea art at a training center during their summer vacation in Nanhe County, north China's Hebei Province, July 15, 2018. (Xinhua/Zhu Xudong)

Children attend a model airplane class at a training center during their summer vacation in Nanhe County, north China's Hebei Province, July 15, 2018. (Xinhua/Zhu Xudong)

Children practice dancing skills at a training center during their summer vacation in Nanhe County, north China's Hebei Province, July 15, 2018. (Xinhua/Zhu Xudong)