回複：To Lovewind

Any special documents I should prepare and carry with?

Here is my list:
Passport with I-94 attached.
Previous I-20s (it is better if you have copy of all previous I-20s. I was asked to show all of my I-20s)
I-485 receipt
AP (both copies)
I-140 approval notice
Driver’s license or some other ID with photo

Is there anything I should pay attention during the travel and re-entry?
Actually it is not going to be difficult. The only thing that they want to make sure is that you are the person in the AP. So it is better if you take some photo ID with you when you go back to China. A driver's licence is good enough.
It is important to carry both copies of AP. INS will take one away and give you back the other one stamped.
They will question you in a room. That is the different treatment from other visa-holders. But the questions should be easy and you have nothing to worry about.

Enjoy your trip.