liquid lubricant

例句：

1. 1. The engine needs a new oil to keep it running smoothly.
   发动机需要新的油来保持顺畅运行。
2. 2.The car's suspension system relies on liquid lubricants for smooth operation.
   汽车的悬挂系统依靠液体润滑剂来保证平稳操作。
3. 3. The machine uses a liquid lubricant to reduce friction and increase efficiency.
   这台机器使用一种液体润滑剂以减少摩擦并提高效率。