And these circular structures are called osteons.

这些圆形结构被称为骨元。

The skin has a layer of closely packed, circular structures.

皮肤有一层紧密堆积的圆形结构。

Amazingly, it would appear that a group of neanderthals broke of stalagmites in the cave and used them to build strange, circular structures.

令人惊讶的是，一群尼安德特人似乎打破了洞穴中的石笋， 并用它们建造了奇怪的圆形结构。