vba如何取消ontime,防止其自动运行

'结束时哪个开始的时间点要与前面的相对应。要定义一个模块变量或全局变量，保证时间点相同
dim ss
Sub proc()
Dim t
t = DateDiff("n", startime, Now())
If exam_s Then
Sheet4.Range("f2") = t & "分钟"
Else
Sheet4.Range("f2") = Format(Now(), "hh:mm:ss")
End If
ss=Now() + TimeValue("00:01:00")
Application.OnTime Now() + TimeValue("00:01:00"), "proc"
End Sub
Sub stoptime()
On Error Resume Next
Application.OnTime ss, "proc", , False
End Sub
'这个是程序中指定停，也可以把, 这二句放在关窗口的事件中
Private Sub Workbook_BeforeClose(Cancel As Boolean)
On Error Resume Next
Application.OnTime ss, "proc", , False
End Sub