drain trap

例句：

1. 1. The drain trap was clogged with debris, causing the water to back up.
   排水沟被堵塞的杂物堵住了，导致水倒流。
2. 2.The engineers had to clear the drain trap before they could start work on the new pipeline.
   工程师们必须先清理排水沟才能开始新管道的工作。
3. 3. The drain trap is designed to prevent sewage from flowing into the storm drain system.
   排水沟的设计是为了防止污水流入雨水排水系统。