8老师好，
以下几个问题请帮忙解惑。
1. 我母亲绿卡回国可以最长呆多久？
-Your mother had better apply for reentry permit to travel to China, which allows her to stay in China for > one year < two years from the date the reentry permit is approved. She can leave US after conducting the fingerprinting, not need to wait for the reentry permit approval. Then, you can mail the approved reentry permit to her later.
2. 如果超过一年以上绿卡就作废了吗？
-If she does not apply for reentry permit, then her green card will be void after her stay in China for more than one year continuously.
3. 如果再来美国是不是还得申请10年签证？
-If her green card is void, she needs to abandon the green card and then, apply for B2 visa to visit you.
她是去年以10年签来的，后来我们给她申请了绿卡。 我母亲有dementia，情绪时好时坏。不过还认识我们，我也说不上在哪个stage上。我们小孩明年要申请大学. 我们都是全职工作。不敢冒风险让她呆在这儿怕影响孩子。我哥在国内今年年初退休。 说老实话大家都不太爱侍候，老太太脾气打年轻时就暴。
先谢谢！
