I am indian citizenship hold indian passport ,i got 6 month double entry visa from hongkong.

hi ,
i got 6month double entry visa from hongkong ,currently i am in china -guangzhou ,next month i have to go for internship in another province, i am so worried ,can i use this multiple visa for my internship ? my visa till septermber 6,2012 ,or should got another x visa ? our teacher replied ,its strictly forbidden to come china with tourist visa and then convert into student visa,i am so worried about that,can i use this multiple [F] double entry visa for my intern or not ,