AIT︰馬綠卡有效否 只有他自己知道 Maintaining Permanent Residence | USCIS You may be found to have abandoned your permanent resident status.............你可能被判定放棄（不是註銷）......所以是否仍然有效最終還是要由移民局做認定
所以，只有移民局才有權判定你所擁有綠卡的有效性，所以你放棄了綠卡後，還要依循正常手續申請正式註銷。
Anyone holding a Green Card who simply leaves the US and moves to another country thinking they are done with the IRS is WRONG.
The IRS expects such persons to continue paying US taxes, unless they file Form 8854 and go through a complicated procedure, that includes a monstrous exit tax for the rich.
