回複：NC pending so long. What will they check in China?

I doubt they will check everyone (maybe they will ask for help if you have lots of hits from their internal database). My wife's NC was cleared within 1 week of filing I485, her school was merged and changed name. Everything same and stuck with NC for three years, and only got cleared after filing WOM. Think of WOM unless you don't care for longer waiting. you can find lots of information from:
http://www.photobaobei.com/greencard/wom.php