Indelibale memories - Zhang Yingying (left) with her younger brother Zhang Xinyang. [Photo provided to China Daily[

"Growing up, I didn't have a lot of opportunities playing with my sister-she was always up there studying," said Zhang Xinyang, Zhang Yingying's younger brother."But she never failed to turn up wherever I was beaten up or bullied by older kids.

"I'll support him as long as he agrees to work hard," wrote Zhang in her diary, faulting herself for not having cared enough for her younger brother, who quit school when he was 15.

She also harbored guilt regarding her parents.

"I called mom and dad today," she said in another diary entry. "Dad is a truck driver now, it's such hard work ... How could I think only of myself?"

Yet for Ye Lifeng, Zhang was simply the best daughter, who, with all work done, would come downstairs and snuggle right beside her in bed, moving ever so gently to avoid disturbing her.

"Yingying was the eyes and ears for her mother, who has never learned to read or write," said Wang, the family lawyer."If she had lived the life of an average girl in town she wouldn't have been able to open that window for her mother, trapped in her own shuttered existence."

Happy times- Zhang Yingying (middle) with her parents and boyfriend Hou Xiaolin. [Photo provided to China Daily]