Sorry, I can only type English.
The interview questions for my mom on 11/06:
1. Why do you want to go to USA?
Visiting my son
2. When he went to USA?
yyyymmdd
3. How does he get GC?
abcdefg
4. How many kids do you have?
Only 1.
5. Do you work?
Yes.
6. How much do you make monthly?
RMB1800
Then the officer went back to talk with someone in the embassy and checked computer for a long time and issued the B-2 visa.
Materials I prepared:
1. I134
2. Employment Verification Letter
3. Bank Statement
4. Pay stub
5. Letter to VO
6. Copy of GC, passport, W-2
7. Invitation Letter
I think it's helpful that my mother filled in her name in DS-156 about who will support the trip.
Hope this helps. Again, I would like to say thank you to everybody here for sharing your knowledge!