如果某種特殊原因必須放棄現在的綠卡，問題
1:是在美國境內先放棄綠卡申請，
-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:還是等到在國內呆上2年（綠卡還在有效期，但離美超過6個月）是否屬於自動放棄，哪還需要填表嗎？
-Just give up it when you return to China. see above.
不隻哪個好點，還是有其他方法
3:放棄後申請十年旅遊簽證會批嗎？
-Normally yes.
4:因孩子和愛人都是美公民，再次申請綠卡容易嗎？
-Yes.
