回复：回复：感叹！

绿卡只有在某些情况下有用， 比如换工作， 回国，或申请公民。否则也没显得有什么用。
-Not really true. Green card holder can have the retirement,social security benefit, medicare/medicaid, etc. But h1 or other non-immigration worker can not have such benefits though they also pay the social security, medicare tax unless they get the green card later.