cut-off valve

例句：

1. 1.The cut-off valve prevents theflow of gas from the pipeline.
   切断阀阻止了气体从管道中流出。
2. 2. Theengineer used a special tool to cut offthe valve and replace it with a newone.
   工程师使用特殊的工具来切断阀门并更换它。
3. 3. The cut-off valveis essential for maintaining the safety of thesystem.
   切断阀对于保持系统的安全性至关重要。