The first one occurred around 150 million to 140 million years ago during the Mesozoic era.

第一次发生在大约1.5亿至1.4亿年前中生代。

The Mesozoic Era, spanning over 180 million years.

中生代，跨度超过 1.8 亿年。

One hypothesis that has gained popularity among paleontologists is the role of extraterrestrial impacts in shaping the Mesozoic area.

有一种假说在古生物学家中越来越受欢迎，那就是外星撞击在塑造中生代地区中所作用。

Researchers say they have made a major discovery straight out of the Mesozoic era.

研究人员说，他们有了一个直接来自中生代重大发现。

And I think for this activity, I'm going to delete " mesozoic" because I don't care.

我想对于这个活动，我要删除“中生代”，因为我觉得它没用。

This would have been especially important in the extreme climate of the early part of the Mesozoic Era.

这在中生代早期极条件下尤其重要。

… now when they found the remains of the Mesozoic mastodon...

他们找到中生代乳齿象化石。

That period is called the Mesozoic Era.

那个时期被称为中生代。

As more fossils of Mesozoic birds were found, more clues started to present themselves.

随着更多中生代鸟类化石发现， 更多线索开始出现。

Most of its fossils date to the Mesozoic, between 252 and 66 million years ago.

它大部分化石可以追溯到 252 到 6600 万年前中生代。

After the Jurassic period came the last period of the Mesozoic Era.

侏罗纪之后是中生代最后一个时期。

The stage was set for the first act of the Mesozoic, the Triassic Period.

舞台是为 中生代第一幕，三叠纪。

Like, " mesozoic" is really technical, you're probably not going to get that on the test, so I will delete that.

比如，“中生代”是非常专业词，你可能不会在考试中遇到，所以我把它删掉了。

It lived in the era before the Mesozoic, in the Paleozoic.

它生活在中生代之前时代， 在古生代。

But for the giant reptiles of the Mesozoic, their dominance turned out to be their downfall.

但对于中生代巨型爬行动物来说， 它们统治地位原来是它们垮台。

These events ushered in the third act of the Mesozoic: The Cretaceous Period.

这些事件迎来了 中生代第三幕：白垩纪。

These external forces began at the end of the Mesozoic, when plate tectonics caused the uplift of mountains in North America and Asia.

这些外部力量始于中生代末期，当时板块构造造成了北美洲和亚洲山脉抬升。

It was during the Cretaceous period that a third major reptilian group began patrolling Mesozoic waters joining the Ichthyosaurs and Plesiosaurs.

正是在白垩纪时期，第三个主要爬行动物群开始与鱼龙和蛇颈龙一在中生代水域巡逻。

So maybe the Mesozoic lifestyle wasn't quite so strictly split between dinos active during the day and mammals active during the night.

因此，也许中生代生活方式并没有严格划分为白天活跃恐龙和夜间活跃哺乳动物。

This would have been especially important in the extreme climate of the early part of the Mesozoic Era. The days were hot, the nights, cold.

这一点在中生代早期极中尤为重要。那时白天很热，晚上却很冷。