像声明一个过程：yan(byval name as string)与
                yan(name as string)有什么区别呢？

Private Sub Command1_Click()
    Dim strB As String
    strB = "strB"

    yanV strB
    Print strB

    yan strB
    Print strB
End Sub

Sub yanV(ByVal strA As String)
    strA = "test"
End Sub
Sub yan(strA As String)
    strA = "test"
End Sub

ByVal是传值，相对应的ByRef是传指（指针）

感谢楼上！！！！