Rail transportation, in a wide sense, covers ordinary railway, intercity railway, suburban railway, high-speed railway and ________________. 铁路运输广义上包括普通铁路、城际铁路、城郊铁路、高速铁路和________________。
A、monorail 单轨
B、urban rail transit 城市轨道交通
C、light rail 轻轨