回复:请问各位关于I-94 and I-20的问题。 多谢各位!
Any non-immigrant in US should have I-94, but I-20 is specifically for non-immigrants in F-1 status besides their I-94s.
http://blog.wenxuecity.com/blogview.php?date=200709&postID=13250
http://blog.wenxuecity.com/blogview.php?date=200804&postID=4128