You won t have any problem getting into China, as i have done this before myself. I have heard that they do occasionally ask you about a one way ticket, however you can just say you are moving on after 30 days and everything will be ok.

After your visa has run out, normally you do have to leave china, and say go to hong kong whilst they convert your visa to a Z visa, however this will depend on what type of relationship your school has with the local government. If they have a good relationship, this can easily be converted without the need for leaving China.

I went to Kaifeng last year, with an L visa, and a one way ticket, and had no problems. My school converted my visa for me and i didnt have to leave China, however you MUST check what the school can do for you!!!!