“The fossil record continues to show that the origin of modern placental mammals postdates or is at the Cretaceous-Paleogene boundary, ” he said.

他说：“化石记录一再证实现代胎盘类哺乳动物的起源是在白垩纪-早第三纪分界点的时候或那之后。

youdao

These discoveries have raised new questions concerning the origin and distribution of early mammals.

这些发现提出了有关早期哺乳动物的起源与分布的新问题。

youdao

These discoveries have raised new questions concerning the origin and distribution of early mammals.

这些发现提出了有关早期哺乳动物的起源与分布的新问题。

youdao