________________________ means power source is an engine or an electric motor scattered between vehicles ( cars) of the train rather than concentrated on the locomotive. ____________指动力源是一台发动机，或一个分散在火车车辆(车厢)之间的电动机，而不是集中在火车头。
A、freight train 货车
B、power centralized train 动力集中列车
C、power distributed passenger train动力分散客车