回複：急問b2延期，急急急，叩謝！

－－－郵寄材料裏的efiling recipt是填完表格之後生成的Confirmation Receipt？還是幾天之後uscis 郵寄過來的official Receipt Notice (Form I-797) ？

-It is the Efiled verification receipt (print it out) and send all the support documents with this receipt to the address indicated in the Efiled verification receipt

－－－到底是郵寄i94原件還是copy？

-Photocopy is OK.

－－－郵寄可以用usps express嗎？還是普通平郵？

-If the address is mailbox, no Express Mail.