1） instruction 只是说有费用 ， 没说怎么付款。 是写check 和表格一起寄走吗？check上面写给谁也没讲
-You can issue a personal check payable to "U.S. Department of Homeland Security". The payment need to be sent together with the I-131 filing (clip it to the top of the form, not staple it).
2）寄挂号信吗？
-Either first class or Express is fine. Up to you.
3）我爸妈的表格分开寄对吧
-Yes.
