Definition: a small, simple instrument that makes a sound when you blow through it Level: B2
裁判吹响了他的哨子，结束了比赛。
The referee blew his ___whistle to end the game.
当我听到外面的那些哨声时，我非常紧张。
I was so nervous when I heard those ___whistles outside.
警察用哨子来指挥交通。
The police officer used a ___whistle to direct the traffic.
