What does BFF really mean?

According to the London Daily Mail, Xie Xu, 18, met his best friend, 19-year-old classmate Zhang Chi, when they enrolled at Daxu High School in Xuzhou, a large Chinese city in the province of Jiangsu. Zhang suffers from muscular dystrophy. It's hard for him to walk, so Xie decided to carry him around campus to be sure he won't miss any classes. The boys live in dorms near the school. Xie carries Zhang from their rooms to the school and back again, also helping him with daily tasks like getting meals and washing clothes. Xie says he carries Zhang about a dozen times each day.  He's done this for three years, so far.

Others have noticed. Vice-principal Guo Chunxi says Xie is a "most beautiful student. He exerts a positive influence on other students, who also help Zhang. With their assistance, Zhang has never once been absent."

 Xie and Zhang are both serious scholars, ranking at the top of their class, and look forward to studying together in college.