The condition of the Sandun Primary School, although it is bigger than the Erdaogou school, was almost the same when Yao was transferred to it. In fact, some young teachers left the school after working there for just one month.

"To tell you the truth, I wanted to leave too. But I couldn't," Yao said. "I grew up in the countryside and I like these children very much. My wife always encouraged me to stay."

Thanks to his good performance, Yao was made the headmaster of the school in 2004, the same year that his wife started working as a substitute teacher there.

Yao pays special attention to comforting other teachers so they feel at home in the school and start liking their job. And Yao and his wife take care of the students as if they were their own children. As for Yao's own children, his daughter has graduated from a college and his son studies in a local junior middle school.

Over the past 22 years, among the graduates of the Sundun Primary School, three have obtained doctoral degrees and dozens have earned a master's or a bachelor's degree.

Jiao Shufeng, a PhD candidate in Chinese history at Shaanxi Normal University, is one of them. He said: "Yao was my first teacher. He helped me cultivate good study habits and methods. He laid a solid foundation for my future academic career. I am lucky to have him as my teacher when I was young." Perhaps inspired by Yao, Jiao said he also plans to be a teacher and help more left-behind children to get better education.

Yao is happy to see parents today attaching great importance to their children's education, and he acknowledges that the poverty alleviation campaign and the rural vitalization program have helped improve the quality of education in the school, which now has computers, sports equipment and books on varied subjects.

But Yao fears the school may have to be shut down in the next few years, because not only is the fertility rate declining rapidly but also more and more migrant workers are bringing their children with them so they can go to school in cities and counties.

"Although I feel sad at the prospect of the school closing down, I am happy that the children can have better education, and strive for a better life," Yao added.