A medical worker sprays disinfectant inside a prefab classroom for the national college entrance exam at a school in Yushu Tibetan Autonomous Prefecture, Northwest China's Qinghai Province, where a powerful earthquake in April killed over 2,000 people, on Sunday, June 6, 2010. [Photo/Xinhua]

A teacher leads students into the exam room for the national college entrance examination at a school in Yushu Tibetan Autonomous Prefecture, Northwest China's Qinghai Province, where a powerful earthquake in April killed over 2,000 people, on Monday, June 7, 2010. [Photo/Xinhua]