We moved back to China last year. The question is whether we can keep our green card active if we pay the tax every year. If the answer is NO, I think we should give up our GC, so we do not need to pay the tax. Thank you very much for your opinions.
-Only only you need to pay tax, but also you need to stay in US physically at least 6 months each year in US regularly. You can not stay in China for > one year continuously unless you have reentry permit which allows you to stay outside US for >1 year <2 years continuously.