Kindergarten children wearing gowns of Doctor Degree throw their graduation hats into the sky at the Hedong District No. 2 Kindergarten in Tianjin, north China, June 17, 2016. Some older children finished kindergarten education here. Photo: Xinhua

Kindergarten children wearing gowns of Doctor Degree throw their graduation hats into the sky at the Hedong District No. 2 Kindergarten in Tianjin, north China, June 17, 2016. Some older children finished kindergarten education here. Photo: Xinhua

Kindergarten children wearing gowns of Doctor Degree throw their graduation hats into the sky at the Hedong District No. 2 Kindergarten in Tianjin, north China, June 17, 2016. Some older children finished kindergarten education here. Photo: Xinhua