There have been several extinction events in the history of the Earth.

地球历史上曾发生过几次灭绝事件。

Geology is the study of the structure and history of the Earth and the other planets.

地质学是研究地球和其他行星的结构和历史的学科。

When we look at the history of life, we see that there are many, many extinction events throughout the last four and a half billion years, that is, throughout the history of the earth.

当我们在回顾生命的历史时，我们发现在过去的四十五亿年里，即在地球历史上，有过很多很多灭绝事件。