keep 绿卡

来源: 于 2010-04-23 15:54:01 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

What is the requirement to keep 美国绿卡? My sister has got 绿卡 and she still has a job in China. Someone told me that she should stay in China less than half year at one time. If you know about it, please tell me. Thank you very much.