我查看了移民局网站，发现这样一段话：
A general guide used is whether you have been absent from the United States for more than a year.
http://www.uscis.gov/green-card/after-green-card-granted/international-travel-permanent-resident
诸位看官，我辛辛苦苦给父母办了移民，事到临头，人家又犹豫要不要来美国了，我都要被气死了。他们让我查查，对绿卡的有效啊，或者发生了什么就会被取消啊是怎么规定的。
看了上边这段话，可不可以这么理解：假如他们在拿到绿卡后就回国，然后每10个月来美国一次，应该是没问题的？
-Yes, but they can not go back and forth too often, otherwise the CBP officer at the port of entry may give them trouble. The green card is for them to live in US permanently, not for use as the border-crossing card. They may apply for reentry permit which allows them to stay in China for > one year < two years.
more than a year ---应当指的是一次， 而不是累计的吧？
-Right.
A general guide used is whether you have been absent from the United States for more than a year.
http://www.uscis.gov/green-card/after-green-card-granted/international-travel-permanent-resident
诸位看官，我辛辛苦苦给父母办了移民，事到临头，人家又犹豫要不要来美国了，我都要被气死了。他们让我查查，对绿卡的有效啊，或者发生了什么就会被取消啊是怎么规定的。
看了上边这段话，可不可以这么理解：假如他们在拿到绿卡后就回国，然后每10个月来美国一次，应该是没问题的？
-Yes, but they can not go back and forth too often, otherwise the CBP officer at the port of entry may give them trouble. The green card is for them to live in US permanently, not for use as the border-crossing card. They may apply for reentry permit which allows them to stay in China for > one year < two years.
more than a year ---应当指的是一次， 而不是累计的吧？
-Right.
