回複：勞工卡和勞工證有何區別？

There is labor certificate (LC), there is also Employment Authorization Document (EAD).The LC application is sponsored by your employer,once you have it granted, you may submit your i-140 then i-485; The EAD application is applicable only after you have your i-485 filed and your Alien number obtained. With EAD you can work and verify your legal status.