reverse pitch airscrew

例句：

1. 1.The aircraft's main engine is a reverse pitch airscrew.
   飞机的主要发动机是一个反向螺旋桨。
2. 2. The engineer used the reverse pitch airscrew to adjust the speed of the machine.
   工程师使用反向螺旋桨来调整机器的速度。
3. 3.The pilot had to reverse the pitch of the airscrew to avoid hitting an obstacle.
   飞行员不得不反转螺旋桨的倾斜角度以避免撞到障碍物。