Before the mass extinction, the top ocean predators were primitive sharks.
在大规模灭绝之前，高等海洋肉食生物是远古的鲨鱼。
2
A newly discovered eel that inhabits an undersea cave in the Pacific Ocean has been dubbed a "living fossil" because of its primitive features.
一种最近在太平洋海底洞穴被发现的鳝鱼因其原始的特征而被冠以“活化石”称号。
3
Numerical simulation of currents of the western North Tropical Pacific Ocean have been carried out by using a barotropic primitive equation model with finer horizontal resolution.