back ward impeller

例句：

1. 1.The backward impeller is responsible for the rotation of the blades.
   反向推进器负责叶片的旋转。
2. 2. The engineer designed the backward impeller to improve efficiency.
   工程师设计了反向推进器以提高效率。
3. 3. The backward impeller is used in many industrial applications to move fluids.
   反向推进器在许多工业应用中用于移动流体。