middleoftheworld, it is possible to obtain divorce gong1 zheng4 using tiao2 jie3 shu1, but that depends on which gong1 zheng4 chu4 you go to... That's an annoying situation in China... I don't know how that would affect your 485 application, but mine is based on marriage to US citizen, uscis must be very strict when inspect my marital history. It wouldn't hurt to prepare more than needed... Good luck!