bleeper

例句：

1. 1. The police officer is using a bleeper to keep an eye on the crowd.
   警察使用一个吹口哨器来监视人群。
2. 2. She bleeped her way through the exam with ease.
   她轻松地用口哨通过了考试。
3. 3. The baby was bleeping happily when he heard his mother's voice.
   当宝宝听到他妈妈的声音时，他高兴地吹着口哨。