'SpeechHypothesizing'没有重载匹配委托'System.EventHandler'

Question

///将语音从微型手机转换为文本

    private void button1_Click_1(object sender, EventArgs e)
    {
       SpeechRecognitionEngine _speechRecognitionEngine = new SpeechRecognitionEngine();
        _speechRecognitionEngine.SetInputToDefaultAudioDevice();
        DictationGrammar _dictationGrammar = new DictationGrammar();
        _speechRecognitionEngine.LoadGrammar(_dictationGrammar);
        _speechRecognitionEngine.RecognizeAsync(RecognizeMode.Multiple);

//错误来自eventhandler函数 //错误是'SpeechHypothesizing'没有重载匹配委托'System.EventHandler'

        _speechRecognitionEngine.SpeechRecognized -= new EventHandler(SpeechRecognized);
        _speechRecognitionEngine.SpeechHypothesized -= new EventHandler(SpeechHypothesizing);

        _speechRecognitionEngine.SpeechRecognized += new EventHandler(SpeechRecognized);
        _speechRecognitionEngine.SpeechHypothesized += new EventHandler(SpeechHypothesizing);

    }
    private void SpeechHypothesizing(object sender, SpeechHypothesizedEventArgs e)
    {
        ///real-time results from the engine
        string realTimeResults = e.Result.Text;
    }

    private void SpeechRecognized(object sender, SpeechRecognizedEventArgs e)
    {
        ///final answer from the engine
        string finalAnswer = e.Result.Text;
    }