Students sit national exam

Traffic policemen stand guard near a center for the national college entrance exam in Hechi, Southwest China's Guangxi Zhuang autonomous region, June 7, 2012. This year 9.15 million students will sit the national college entrance exam, or gaokao, on Thursday and Friday, with an expected average admission rate of 75 percent, the Ministry of Education said. [Photo/Xinhua]

A teacher cheers students before they sit the national college entrance exam in Hengshui, North China's Hebei province, June 7, 2012. [Photo/Xinhua]