Students left-behind by their parents who leave home to work hold a big, self-made greeting card with blessing words in Huanfeng No 3 Primary School in Hanshan county, Ma'anshan city, East 皇冠体育app's Anhui province, Dec 26, 2011. The greeting card will be sent to their parents to convey their thanks and blessings. [Photo/CFP]

Students left-behind by their parents who leave home to work, show a self-made greeting card in Huanfeng No 3 Primary School in Hanshan county, Ma'anshan city, East 皇冠体育app's Anhui province, Dec 26, 2011.[Photo/CFP]