circular function

例句：

1. 1. The circle of light around thetree is very bright.
   围绕树的光环非常明亮。
2. 2. The car was driving in acircular motion.
   汽车在圆周运动中行驶。
3. 3. The map shows the city in acircular layout.
   地图以圆形布局展示了这个城市。