In the mine drainage system many drainage pumps must work correspondly.
In the mine drainage system many drainage pumps must work correspondly.
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。
In the mine drainage system many drainage pumps must work correspondly.
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。