当（），正线、辅助线通信列车采用自动区段闭塞法组织行车。
参考答案：区域控制器（ZC）或基于 AP 的车地无线通信故障，点式设备完好时
The Smiths have gone to New York for their holiday, with an old servant ____ their house.
A．looking after
B．look after
C．having looked after
D．looked after
—What's the date today?
—_______ [ ]
A. It's Monday
B. It's July 17th
C. It's Monday the 17th
D. It's July 2003
