lubricating agent

例句：

1. 1. The engine needs a lubricating agent to keep it running smoothly.
   发动机需要润滑剂来保持顺畅运行。
2. 2.The car's engine is a lubricating agent that keeps the moving parts from wearing out.
   汽车的发动机是一种润滑剂，它使移动部件免于磨损。
3. 3. The technician used a lubricating agent to remove the old oil and replace it with fresh oil.
   技术人员使用了润滑剂来去除旧油并更换成新的油。