x=12                                         x=12

　　　　 Call Fun ( x )                                  Call Fun ( x , z)

　　　　 Print z                                        Print z 

　　　 End Sub                                      End Sub

　　　 Sub Fun ( y )                                  Sub Fun ( y , z )

　　　　 z = y * y                                      z = y * y 

　　　 End Sub                                      End Sub 

（C）Private Sub Form_Click( )                  （D）Private Sub Form_Click( )

         x=12                                         x=12

         Call Fun ( x )                                  Call Fun ( x , z )

         Print z                                        Print z

       End Sub                                      End Sub

       Sub Fun ( Byref  y )                             Sub Fun ( Byref  y , z )

         z = 12 * 12                                    z = y * y

       End Sub                                      End Sub

7．       设有如下程序：

Private Sub Command1_Click()

Dim sum As Double, x As Double