回複：朋友持綠卡入境時，被邊關警察警告，這是你最後一次持卡入境，然後把綠卡還他。

這是警察唬人，不讓他再來回跑綠卡嗎？
-No 警察唬人. If he does not have reentry permit, he will not be allowed to enter US next time and his green card will be take away and cancelled. The green car dis for him to live in US permanently, not be used as crossing-border card.