China's many left-behind children are a cause for mounting concern. While parents work in distant cities, their children are left to grow up without parental guidance. But loneliness is teaching some of these youngsters the importance of independence and maturity.

Jiang Nanyan is a primary school teacher in a county of Chongqing municipality.

Half of her students are left-behind children.

She has special feelings for kids who have been separated from their parents for years, as she experienced the same situation when she was young.

Jiang Nanyan, a elementary school teacher, said, "Being left-behind is hard. You can't express your feelings because your parents are not with you. Even now I still feel sad. "

Although Jiang Nanyan's tough experience was years ago, she still hasn't got over it.

Facing kids who have similar childhoods, all she wants is to give them care and support.

Jiang Nanyan said, "I often remind my students of good habits, for example, to wash their clothes. When their parents call me, I often tell them to make more calls to their kids and show more care. For some senior students' parents, sometimes I want to persuade them to come back because their kids are experiencing puberty and they need them."

Being alone is hard, but it is this feeling of loneliness that made Jiang learn to be strong. And now she is telling her students how to face challenges with a smile.

Jiang Nanyan said, "I used to say I was a cactus and the pricks are not to hurt others but to protect myself. Learning to be self-reliant and strong is important."

The number of left-behind of children is also growing in China. 14-year-old Yang Wentao is learning the same life lessons that Jiang Nanyan learnt years ago.

Yang Wentao said, "The bags are full of stones, I often lift them as an exercise to gain strength. I love studying because it can fulfill the emptiness of my lonely heart."

Yang's parents are working in Shanghai. They call him once a month. Being alone means the boy has learned to take care of himself much sooner than other children.

Yang Wentao said, "I washed the sheets last week and I make the bed myself."

Without his family around him, Yang's classmates have become his support network.

Yang Wentao said, "When I am upset, I turn to my classmates. After talking with them, I feel relieved and much better."

Yang says his ambition is to become a geologist because his experience has taught him how to adapt to a harsh environment.

(CCTV April 10, 2009)