回複：need info for AP going back to China, Thanks

1, when leaving, at LAX, I should turn in I-94, I have the original F1 one and a newer Hib one, which one to turn in? or both??
ANswer: The white card which stappled on your passport when you entered US last time at airport.

2, when come back, at Shanghai airport, what do I need to show beside AP, to get on the plane?

Answer:passport and AP (probably I-485 receipt)

3, How long does it take for AP to get through immigration, when I come back, 1 hr or 2 hr? Since I need to catch a train.

Answer:Depend on how many people on line.

I understand since I am coming back to the same position, my H1B is still valid until next renew, right?

Answer:you need to contact with your attorney, it is said if you use AP , you will not come back to H-1B status unless you leave US and reget a new H-1 visa.