Expert Zheng Zhiyuan teaches quake escaping skills to students at the Nongzhang middle school in Yingjiang County, southwest China's Yunnan Province, March 17, 2011. A quake drill was held Thursday in the county, which was hit by a 5.8-magnitude quake last Thursday. Schools in the county are enforced to carry out at least two drills every semester after a 5.9-magnitude quake hit Yingjiang in 2008. [Xinhua/Qin Qing]