tone signalling

例句：

1. 1. The music has a rich tone.
   这音乐有丰富的音色。
2. 2. The singer's voice has a clear tone.
   歌手的声音清晰有力。
3. 3. The piano player needs to adjust his tone for the next piece.
   钢琴家需要调整他的声音来演奏下一首曲子。