如何让Wav音频文件中间产生3秒暂停

Const SSFMCreateForWrite = 3
Dim Str1,Str2
Str1 = "测试字符串1" '这里输入要输出的声音
Str2 = "测试字符串2" '这里输入要输出的声音
Set objVoice = CreateObject("SAPI.SpVoice")
Set objFile = CreateObject("SAPI.SpFileStream.1")
objVoice.Rate = 1  '获取和设置声音说话速度。
objVoice.Volume = 100   '获取并设置相应的体积（响度）的语音水平。
objVoice.AllowAudioOutputFormatChangesOnNextSet = False  '获取并设置标志，指定是否允许调整声音输出格式的音频自动。
objVoice.Speak Str1
Wscript.sleep 3000   '朗读时产生3秒暂停
objVoice.Speak Str2
objFile.Open "测试声音.wav", SSFMCreateForWrite '输出路径
Set objVoice.AudioOutputStream = objFile
objVoice.Speak Str1
'?????????????????????????如何让Wav音频文件中间产生3秒暂停???????????????????
objVoice.Speak Str2
objFile.Close
Set objVoice.AudioOutputStream = Nothing
Set objVoice = Nothing