internal drainage system

例句：

1. 1.The new building has a sophisticated internal drainage system that helps to prevent water leaks.
   这座新建筑拥有一个复杂的内部排水系统，有助于防止漏水。
2. 2. The engineer designed the internal drainage system carefully to ensure it would work efficiently.
   工程师仔细设计了内部排水系统，以确保它能够高效地工作。
3. 3.The construction of this internal drainage system is expected to reduce the risk of flooding in the area.
   预计这项内部排水系统的建设将降低该地区发生洪水的风险。