It is possible, but not guaranteed.

如果我們在回國前（5月底）拿不到綠卡，可不可以用我們的返美證回國，而不會在返美時遇到問題？
-No problem even if your green card is approved during your travel in China as long as your AP does not expires before you come back.

我們這種情況，回還是不回，您的建議是什麽？ 多謝！