Event Form1.CheckBox1.Click
    call 单选(1)
End Event
Event Form1.CheckBox2.Click
    call 单选(2)
End Event
Event Form1.CheckBox3.Click
    call 单选(3)
End Event
Event Form1.CheckBox4.Click
    call 单选(4)
End Event

Sub 单选(xx)
    If xx <>1 Then 
        Form1.CheckBox1.Value =0
    End If

    If xx <> 2 Then 
        Form1.CheckBox2.Value =0
    End If

    If xx <> 3 Then 
        Form1.CheckBox3.Value =0
    End If

    If xx <> 4 Then 
        Form1.CheckBox4.Value = 0
    End If
End Sub