８老师你好，
我为我父母和公婆去年６月申请绿卡，我父亲和公公的绿卡在今年６月刚批下来。因我婆婆去年身体情况，公婆在去年８月份就回国了，我今年６月回国，上周回来接到信，我父亲和公公的绿卡在今年６月批了，我母亲和婆婆的还没批。对公婆的这事我不知该如何处理。因公婆在去年８月份就回国了，公公的绿卡今年６月批了, 但他已回国一年了，他是否可来美？
-He had better return to US before the AP expires. If he can not retunr to US shortly, he had better come back to US within 6 months using the green card.
是否需要马上来美？
能否等到我婆婆的绿卡批了一起来？
-She had better return to US before the AP expires. Otherwise, there will be trouble if the green card application is denied (Of course, it will be fine if the green card is approved).
最多可在中国呆几个月绿卡还有效？我们该怎么办？他能否进入美国？
需要申请白皮书吗？谢谢８老师！
