circular main

例句：

1. 1.The circle is the shape of a full circle.
   圆形是一个完整的圆的形状。
2. 2. The car's wheels are circumferential.
   汽车的轮子是环形的。
3. 3. The planets orbit around the sun in circumferential paths.
   行星围绕太阳以环形路径运行。