回複：出現這種問題多半是材料沒組織好。

I don't know how much money you can earn. For me, why should I spend time on this if there is a professinal who can do this? This is simply not my job. I would rather have this time and energy for my own research? If money can buy your time, why not do it? As for the reason of RFE, have you heard that lots of parents just cannot get a visiting visa to meet their children in US? I think NIW approval is very subjective and it depends on the immigration officer who reviewes your memo. By the way, I have no doubt that my case will be approved eventually.