Urgent:请各位给个建议I-485 Biographic

dear friends,

I got a critical problem in filling the Biographic Information (Form G-325). I worked 2 years in Nanjing before coming to USA. I don't have a stable address in Nanjing (I had lived in 5 different rented house). While I have a house (permenant address) in Wuxi. But I live in Wuxi only a few days every month. What address I should use for the Last Residance Address Outside USA of More Than One Year?

Is form G-325 very important? What it is function anyone knows?

Any relevent information/suggestion would be greatly appreciated!!!谢谢!!!