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.