In 2018, during a reunion with students who enrolled in 2005, Lin found that a student who works as a civil servant in Lhasa is also a volunteer teacher at a school and he reads novels to children like she did.

"He told me that he was impressed by the vitality and perseverance of the characters in the novels I read and wanted to do the same thing to his students. I was surprised that a small part of my routine work influenced him for such a long time," Lin said.

However, Lin feels quite guilty about her son, now a junior in university, because she said she hadn't cared or taught him properly.

"When he was a child, I didn't read any novels or bedtime stories to him because I usually had a sore throat after a day's work and couldn't speak too much but only hug him to show my love," she said.

Lin's husband, a contractor, traveled across the country to work on construction sites all year round when their son was 4 and didn't fix his workplace in Sanming until the boy attended middle school.

"He has a poor reading comprehension and can't concentrate on research or things like that. I guess that's because I and my husband didn't give him enough care or instruction," Lin said. "However, my students also call me mom and they also need my love."

Lin is happy to see her and her colleagues' efforts paid off as the majority of their students returned to Tibet and work as soldiers, bank clerks, doctors, policemen, teachers and civil servants.

"Most of them chose to return to Tibet after college graduation because the region needs local talent and they can get more chances there," she said.

Since the Liedong Middle School set up Tibetan classes in 1995, more than 1,200 students got the chance to continue their study in universities. More than 800 students went back to Tibet for work after graduation.

"Every time I chatted with my students and found that they performed well in their positions to boost development in Tibet, I reaffirmed my original intention to be a teacher for more children like them," Lin said.

During the two decades, Lin found it easier to teach Tibetan students year after year as new recruits are becoming more knowledgeable and better educated.

"Children from Tibet now have a larger amount of reading and better communication abilities. That may be due to better elementary school education in Tibet and highly educated parents," she said.

Lin said that in near future, Tibetan children will not have to travel far to other provinces for better education because more developed provinces and cities are helping build and upgrade schools in Tibet. More and more new schools were built in the region.

For example, in 2014, Lhasa-Beijing and Lhasa-Jiangsu experimental middle schools were put into use. The two local governments separately sent about 50 teachers to aid with teaching.