An employee introduces the PanGu Presentation (PGP), a dual-platform for teaching, to a teacher on Nov 18 at the 13th China Hi-tech Fair in Shenzhen. The PGP was jointly developed by Shenzhen ACTO Digital Video Technology Co Ltd and the Central China Normal University. The annual fair will be held in Shenzhen from Nov 16 to 21, 2011. [Photo / chinadaily.com.cn]