Caution: I am Chinese myself so don't take this comment as an attack on Chinese students in general.
It's been noted that in some Chinese universities, you can literally "network" your way to getting a great
LOR from renowned professors. That is,
(i) You study under instructor / professor XYZ
(ii) You're a great student of this instructor's class
(iii) Unfortunately, XYZ is not renowned but he likes you and wants to help
(iv) XYZ knows a renowned professor ABC
(v) XYZ "recommends" the student to ABC and ABC writes a fantastic letter for this student even though he may not have even met this student ever in his life.
Again, to all the Chinese students / members on TM, don't take this as an offense. It's just an observation from my experience in China.