节拍器

例句：

1. 1. The dancers use a metronome to keep time during their performances.
   舞者们在表演时使用节拍器来保持时间。
2. 2. The music teacher recommends using a metronome when learning to play the piano.
   音乐老师建议学习弹钢琴时使用节拍器。
3. 3. During the rehearsal, the musicians all have to beat out the rhythm with their hands.
   排练期间，所有音乐家都必须用手打出节奏。