Calacea
钙质海绵目
🗣️ 情景例句
I think aerobics is easy.
我觉得有氧运动很容易。
He who does not advance falls backward.
不进则退。
The remains of plants and animals that lived on land are much more rarely preserved, for there is seldom anything to cover them over.
曾在陆地上生活过的动植物的遗体被保存下来的更为罕见，因为陆地上几乎没有什么东西覆盖它们。