1、拿到移民签证后还要交绿卡申请费吗？EB1a类的
-You only need to pay the immigrant fee which is used to produce the plastic green card. See:
https://www.uscis.gov/file-online/uscis-immigrant-fee
https://www.uscis.gov/tools/how-do-i-customer-guides/how-do-i-pay-uscis-immigrant-fee
2、入关以后要多久可以拿到绿卡？
-You become a green card holder immediately after you entering US. You will receive the plastic green card in about one month.
3、在拿到绿卡之前可以短期回国吗？
-Yes, but if you go back and forth between China and US too often, you will have trouble. So, you may apply for reentry permit which allows you stay in China for > one year < two years.
必须回国，因为国内还有生意不能长时间离开
4、如果主申请人最后放弃绿卡，会取消副申请人绿卡吗？
-No.
多谢8老师
