She instructs music once a week at a middle school.她在中学每周教一次音乐课.Dr. Williams instructs us in botany.威廉博士教我们植物学.She instructs a class in chemistry.她给某班学生上化学课....
每晚你都会听见炼钢厂的下班哨声。Every night you could hear the whistles of the steel mill.裁判最后吹响了终场的哨声。The referee finally blew the whistle to stop the game.乘务员哨声一响,司机开动机车.At the conductor's whistle the engine - driver starts his l...