感谢一路上8老师和有经验的伙伴们解答。我父母广州面试顺利过关。面试完后太兴奋也没问如何能拿到护照和签证，是给邮寄到家里吗？
-I don't know. You may contact the US Embassy.
（我妈说是问了要不要交邮寄费，被告知都是免费的。好像和网上得到的信息不一样：非广州需要邮费的。而且也没有收$220移民费，这个移民费啥时候交呀。）谢谢解答。-When the Embassy send the passport with the visa back to your parents, they will also send the instructions how to pay the immigrant fee, then you can pay it following the instructions before your parents land US.
