free rappel

例句：

1. 1. The athlete jumped freely from the top of the tower and fell to the ground.
   运动员从塔顶自由地跳下来，落到了地上。
2. 2. The ship was free falling through the clouds.
   这艘船正自由下落穿越云层。
3. 3.The pilot controlled the plane's free fall to avoid hitting an object.
   飞行员控制着飞机的自由落体，以避免撞击物体。