A.The workers on the underground platforms were replaced by machines.
B.It became the first completely automatic railway in the world.
C.A completely automatic line was added to its network.
D.Computers began controlling the trains on the line.
第5题
A.前级线路保护瞬时跳闸。重合闸动作后,若是永久性故障,各级线路保护选择性跳闸
B.线路保护选择性跳闸。重合闸加速动作重合。
C.线路保护选择性跳闸。重合闸动作后,若是永久性故障,各级线路保护加速跳闸
D.前级线路保护瞬时跳闸。重合闸动作后,若是永久性故障,各级线路保护加速跳闸
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