Ordovician

剑桥词典

from or referring to the period of time between about 485 and 445 million years ago, in which there were many different types of animals in the sea , including vertebrates (= animals with back bones ), but no life on land
奥陶纪的（距今约4亿8千5百万年至4亿4千5百万年前间，此时水中已有许多动物包括脊椎动物，但是陆地上还没有动物）
the Ordovician period 奥陶纪
Ordovician fish 奥陶纪的鱼类

the Ordovician

noun [ 单数名词 ]

the Ordovician period
奥陶纪 返回 Ordovician