叉形

例句：

1. 1. Theaxial symmetry of the planets is fascinating.
   行星的轴对称性令人着迷。
2. 2.The axis of the Earth's rotationis perpendicular to its orbit.
   地球自转的轴线与其轨道垂直。
3. 3.The axis of the new building runs throughthe center of the city.
   新建筑的轴线穿过市中心。