我父母正在綠卡等候中，想要用Advance Parole Document 回國幾個月。根據目前的時間，他們在中國的時候綠卡大概能下來。綠卡下來時他們不在美國會不會有什麽影響？
-No as long as they have the approved AP before they leave US.
回來入境應該用AP還是綠卡？
-AP is fine. Tell the IO at the port of entry when they enter US that their I-485 is approved during their travel in China in this case. You may write a letter for them to explain it to the IO if your parents do not understand English, and then your parents just present the letter to the IO when they enter US.
