circumferential rib

例句：

1. 1. The car was parked in a circular pattern around the tree.
   汽车停在树周围成圆形。
2. 2. The moon is always visible from this vantage point due to its circumferential position.
   由于其周长位置，月亮总是可以从这个观察点看到。
3. 3.The circumferential boundary of the city limits is marked by a large clock tower.
   城市边界的周长由一座大钟楼标记。