回复：帮姐姐申请绿卡

 我已是公民。 我想为我姐姐一家申请绿卡。 如何操作好一些？

-File I-130 and then, wait for Ntional Visa Center to send you instructions and just follow the instruction to do what they ask you to do.

先申请父母的绿卡， 五年后父母成公民， 再让他们为我姐一家申请， 还是现在直接由我为我姐申请好一些？

-Up to you, you may do it now.

如果我现在就为我姐申请， 是不是他们在拿到绿卡之前不能入境？

-Only your sister can not get the B2 visa due to the immigration intent.