父母B2签证来美，现在已呆了超过6个月多几天，本想等我下星期公民后给他们办绿卡，但他们不想再呆下去，很想回国。我的问题是：
1． 如果我公民后马上递了绿卡申请和回美纸申请，大概多久能够完成打指纹和拿到回美纸？
-About 2 to 3 months, case by case. But if they can go to the local USCIS to try to see whether they can get the emergency AP after they receive the I-485 receipt and I-131 receipt.
2． 如果他们不申请绿卡现在回去，会不会因为逾期下次再来的时候有麻烦，
-Their B-2 visa stamp is void even if it does not expire yet. So, they needs to apply for a new B-2 visa to come back. Just explain to the VO that because the air ticket problem reaulted in their overstay a few days. It should be fine.
有没有10天的grace period？
-No.
