8老师你好，之前给父母申请绿卡时我在论坛上向您请教了许多问题，非常感谢您的无私指导，帮助我们顺利获批！我现有另外一个问题，我母亲收到绿卡以后，因为身体原因需要手术第二个月就回国了，我父亲也一起回去了。因为手术和之后的恢复期我拿不准多久所以在他们离开之前给他们提交了131申请回美证。
据说回美证的期限是2年，但是不知道是提交日期往后推两年-No.
还是获批日期上往后推两年？
-Yes.
我母亲的手术做完以后需要定期复查至少一年半到两年，这个期间如果回美证一直不批他们可以一直待在国内吗？
-Normally it is fine if the reentry permit application is approved later, but if their reentry permit is denied, then they need to return to US within one month from the date the I-131 was denied and explain to the officer at the port of entry that their reentry permit application was denied and they need to reenter US to file the appeal (show the I-131 Receipt Notice and the Denial Notice to the officer).
有没有境外滞留的时间上限要求？
他们有回美证的receipt和手术证明，如果下次返美这些足够保证他们顺利入境吗？
-If they returnt to US during the I-131 pending, bring these documents you mentioned If the reentry permit was approved, they just need to show the reentry permit.
再次谢谢您！
