大多数人都提供 employment verification letter 用以证明现在和将来继续受雇。工资单是只证明过去受雇,不说明现在和将来。
关于如何装信封:
If you are sending more than one case in an envelope, clearly separate the cases by rubber band or clip fasteners.
如何装信封链接:
http://www.uscis.gov/forms/forms-and-fees/general-tips-assembling-applications-mailing