The school serves five villages and the average age of its 34 students is 13.

Zhang joined villagers to renovate the school into a structure of bricks, tiles and cement in 2007. The government bought the materials.

He points to a mountainous path leading from the school gate he says he and his students widened over three years.

"We could only work when it rained because the earth was too hard unless it was soaked," he recalls.

Zhang makes 1,000 yuan ($159) a month as a temporary teacher and is anxiously waiting for the local government to organize a certification exam. His salary will double if he passes.

Zhang's wife, Gao Longhong - a local high school graduate - is four months pregnant. They wed last year.

"My wife used to work as a migrant in Zhejiang province and always asks me to find a better job in eastern coastal cities," Zhang says.

"But I was born here. I'm attached to this land. If I leave, the children will probably drop out of school.

"She'd be satisfied if I got the certification. But it has been 10 years. I don't know when the government will host the exam."