sewerage system        
[das] 道系统。
sewerage system

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[das] 道网络。道系统。
sewerage network, sewerage system, network of sewers

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[die] 排系统。排设备。脱设备。
drainage system, drainage plant, sewerage system, sewerage network, dehydration plant

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[die] 排污系统。
foul sewerage, sewerage system