It began with a study one of them did on a dolphin, who had been trained to recognize a particular high-pitchedtone.
首先，他们中的一个人对海豚做了一项研究，训练它识别一种特殊的高音。
2
We should use a moderate tone of voice, and avoid speaking in a sharp, high-pitched voice, which gives people the feeling that we are showing off or arguing.
尤其要避免用尖锐拔高的音调讲话，令人感觉你在卖弄本事或争论。
3
Be careful about the tone of your voice. Keep it evenly moderated and avoid getting a high-pitched, whiny or tearful tone.