manual lubrication

例句：

1. 1. The manual lubrication of the gears is essential for smooth operation.
   齿轮的手动润滑对于平稳运行至关重要。
2. 2. The technician used a special lubricant to manually lubricate the gears.
   技术员使用了一种特殊的润滑剂来手动润滑齿轮。
3. 3. The manual lubrication system is designed to prevent wear and tear on moving parts.
   手动润滑系统旨在防止移动部件的磨损。