C#UWP语音识别器问题

我正在开发UWP，希望使用语音识别器。它应该只对“下一步”和“上一步”作出反应。但通常，它会将“下一步”识别为“返回”。我的代码如下。如何解决这个问题

var defaultLanguage = SpeechRecognizer.SystemSpeechLanguage;
        _speechRecognizer = new SpeechRecognizer(defaultLanguage);
        _coreDispatcher = CoreWindow.GetForCurrentThread().Dispatcher;
        var constraintList = new SpeechRecognitionListConstraint(new List<string>() { "Next", "Back" });
        _speechRecognizer.Constraints.Add(constraintList);

        var result = await _speechRecognizer.CompileConstraintsAsync();
        if (result.Status == SpeechRecognitionResultStatus.Success)
        {
            _speechRecognizer.ContinuousRecognitionSession.ResultGenerated += ContinuousRecognitionSession_ResultGenerated;
            _speechRecognizer.ContinuousRecognitionSession.Completed += ContinuousRecognitionSession_Completed;
            await _speechRecognizer.ContinuousRecognitionSession.StartAsync();
        }

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不幸的是，你在语音识别方面遇到了困难，有时它无法准确识别你所说的话

我推荐的一件事是利用你们得到的结果。通过自信，你可以决定是接受结果还是尝试让用户重复他们所说的

private async void ContinuousRecognitionSession_ResultGenerated(SpeechContinuousRecognitionSession sender, SpeechContinuousRecognitionResultGeneratedEventArgs args)
    {
        {
            await _coreDispatcher.RunAsync(CoreDispatcherPriority.High, () =>
            {

                string command = args.Result.Text;
                Messenger.Default.Send(new VoiceReactMessage(command));
                switch (command)
                {
                    case "Next":
                        SetHorizontalOffset(-ItemsPanelRoot.ActualWidth);
                        break;
                    case "Back":
                        SetHorizontalOffset(ItemsPanelRoot.ActualWidth);
                        break;
                }
            });
        }