我們2007年拿的綠卡，老公去年開始在中國工作，為保綠卡他每半年回美國2周。去年年底他申請了白皮書，打完指紋後回中國。今年年初我收到了白皮書，並快遞給在中國的老公。他將與這周在回美。我的問題是在入關時他有沒有必要出示白皮書？多謝指教！
-He had better show the 白皮書 to the CBP officer if he has gone back and forth between China and UAseveral times. Anyway, showing the 白皮書 does not have any negative effect, but may have it if not show 白皮書.
