A staff member presents a set of seals of the Qianlong period (1736-1795) of Qing Dynasty (1644-1911) during a preview of Sotheby's Fine Art Chinese Ceramics and Works of Art autumn sales in south China's Hong Kong, Aug. 28, 2013. The auction will be held at Hong Kong Convention and Exhibition Centre on Oct. 8, 2013. (Xinhua/Li Ying)