我必須用綠卡回美嗎，
-Yes. Two choices for you:
1. Print out the online I-485 approval information and then, bring your passport, the I-485 approval information and your I-485 receipt to the USCIS local office to see whether you can get the green card stamp on your passport and use the green card stamp to travel to China. Explain to the IO that you have planned to China for a while by using AP, but you just found out that your I-485 was approved online and you can not wait for your formal green card, thus you need the green card stamp to travel to China;
2. Just go to China and ask someone to receive the green card for you and then, mail it to you in China.
還是用AP入關就可以，因為很可能綠卡沒收到，我就走了。非常感謝。
