Postgraduate volunteers who are about to set out on their obligation as assisting tutors attend the setting-off ceremony, in Guiyang, southwest China's Guizhou Province, August 25, 2009. [Xinhua]

Two postgraduate volunteers unfurl the streamer with the collective signatures of volunteers who are about to set out on their obligation as assisting tutors during the setting-off ceremony, in Guiyang, southwest China's Guizhou Province, August 25, 2009. [Xinhua]