greencard still valid into US?

My parents have greencards. But they went back to China and never return in two years. Are their greencards still valid for entry to US?

所有跟帖： 

• 回複：greencard still valid into -carebears- ♀ (2 bytes) () 12/21/2004 postreply 11:16:54

• 無效了，超過半年住在美國以外的，應該申請回美證，綠卡隻用於半 -年以內，重新申請綠卡- ♀ (0 bytes) () 12/22/2004 postreply 08:08:33

• When GC leaves US, there is no -SAMUEL- ♂ (246 bytes) () 12/22/2004 postreply 12:59:52

• 別的國家我不知道，要是回中國的話 ---- -Bodd- ♀ (182 bytes) () 12/22/2004 postreply 13:29:15