做一个VB倒计时，说明控件，最好附图

Dim time0%
Private Sub Command1_Click(Index As Integer)
Timer1.Enabled = True
If Index = 0 Then time0 = 5
If Index = 1 Then time0 = 10
If Index = 2 Then time0 = 15
If Index = 3 Then time0 = 20
If Index = 4 Then time0 = 30
If Index = 5 Then time0 = 60
If Index = 6 Then time0 = 90
If Index = 7 Then time0 = 120
If Index = 8 Then time0 = 300
If Index = 9 Then time0 = 600
If Index = 10 Then time0 = 900
If Index = 11 Then time0 = 1800
If Index = 12 Then time0 = 2700
If Index = 13 Then time0 = 3600
If Index = 14 Then time0 = 5400
If Index = 15 Then time0 = 7200
If Index = 16 Then time0 = 9000
If Index = 17 Then time0 = 10800
End Sub

Private Sub Command2_Click()
Command3.Visible = True
Command2.Visible = False
Timer1.Enabled = False
End Sub

Pri