they see their parents a couple of times a year. 12-year-old wang bing is the most outgoing and lovesread. >> ( translated ): i think my sister is very brave. my brother is quite naughty. we know how to take care of ourselves here. >> reporter: the children stay in their school dormitory during the week. on weekends and holidays, they often cook and wash for themselves. >> ( translated ): my parents are working in guangdong province. i don't know what they do. they don't tell me. it's boring here, just us three children. i miss them. >> reporter: most so-called" left-behind children" rely on grandparents, but not all can provide the care needed. these children's maternal grandmother lives a 40-minute walk away along a mountain path. sometimes she comes to help with farm work and keep an eye on them, but she has other fields to tend, and younger grandchildren to look after. in such cases, older girls often take on the role of mother. 14-year-old wang ying resents the burden placed on her, and refuses to speak to her parents on the phone because she finds it too upsetting. >> ( translat