I read the reply to my question.(my question was about viza for my mother and my sister to visit me in china).
my chinese university can write a letter on university letter's form that i am student and my family can come and visit me with sign and stamp.
but china embassy in iran has said it needs to have official invitation letter, somthing same as jw202 form.
i can not prepare that one.how i should do?
thanks for your guidance .