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举一反三
【单选题】Subways are underground trains, which usually operate 24 hours a day. They are found in larger cities and usually run between the suburbs and the downtown area. Maps and schedules are available from t...
A.
within downtown areas
B.
away from city centers
C.
in or outside big modern cities
D.
between suburbs and city centers
【多选题】下列对于室内工艺管道的安装，正确的是（）。
A.
室内管路敷设应有坡度，坡度方向一般均为顺介质流动方向
B.
管道与管道或设备连接中不得强力对口，不允许将管道与阀门的重量支撑在设备上
C.
供液管路不应有“口袋”（即下凹现象）
D.
输送易燃易爆介质的管路，不得敷设在走廊、楼梯和生活间