Hong Kong youth watch the show which is performed by youth of both Zhejiang and south China's Hong Kong at Zhejiang University in Hangzhou City, capital of east China's Zhejiang Province, July 31, 2017. The exchange activity of youth from Zhejiang and Hong Kong for celebrating the 20th anniversary of Hong Kong's return to the motherland started in Zhejiang on July 30 and will last until Aug. 4. About 2,000 youngsters from Hong Kong participated in the activity. (Xinhua/Weng Xinyang)