如果某种特殊原因必须放弃现在的绿卡，问题
1:是在美国境内先放弃绿卡申请，
-You had better go back to China and then, submit the green card abandonment application, i.e., file I-407. See thiss link:
Abandonment of Status (Form I-407) - U.S. Embassy & Consulates in China
If you give up the green card in US, then you will have no a legal status in US, resulting in your unlawful presence.
2:还是等到在国内呆上2年（绿卡还在有效期，但离美超过6个月）是否属于自动放弃，哪还需要填表吗？
-Just give up it when you return to China. see above.
不只哪个好点，还是有其他方法
3:放弃后申请十年旅游签证会批吗？
-Normally yes.
4:因孩子和爱人都是美公民，再次申请绿卡容易吗？
-Yes.
