英文: In the mine drainage system many drainage pumps must work correspondly.
中文: 摘要在煤矿井下的排水系统中,需要多台排水泵协调地工作。英文: It is the key to the sustainable development of drainage area that interests in drainage area is harmonized by the drainage area management institution.
中文: 只有将流域管理机构和协调流域内部利益紧密结合起来,才是流域可持续发展的关键。英文: Is there adequate drainage where needed?
中文: 需要排水的地方其排能是否足够?英文: It is preferable to connect outlet of test ball valve and drainage outlet with drainage pipeline.
中文: 最好将试验球阀出口和排污口接排水管。英文: The drainage system has been aged.
中文: 排水系统已经老化了。