回複：求助：請大家指點一下怎麽樣保持綠卡有效

no inexpensive way if you and child will continue to live in HK. Try to get another reentry permit in US, but with your 3rd and 4th years out of US and no family in US, reentry permit doesn't necessarily work.

There are expensive ways for the rich if they keep expensive business and properties in US. I am talking about multi-million dollar assets. Then your lawyer can easily help you keep GC.