Dinosaurs have been extinct for millions of years.

恐龙已经灭绝几百了。

You can't be too careful these days.

还是小心驶得船啊。

450,000 years old, 4.5 million years old, 4.5 billion years old or 4.5 trillion years old?

45、450、45还是4.5前呢？

Cereal processing has a history of over 10,000 years.

谷物加工的历史已有上。

I hope you enjoyed the last 10,000 years.

希望你们享受最后一。

What happened about 250 million years ago?

五千前发生了什么？

Modern humans arose in Africa about 200,000 years ago.

现代人类大约在20前出现在非洲。

It takes 10,000 years to wear away an inch of granite.

按一英尺花磨一计算。

In geologic time, a million years is recent history.

在地质学角度看来，一百前属于近代历史。

Simbakubwa was a member of an animal group that appeared 62 million years ago.

非洲巨狮是6200前的一类物种。

This tusk is over 30,000 years old.

这只象牙已经有3的历史了。

Collagen probably cannot last longer than that.

胶原蛋白可能不能存在超过一。

About 10,000 years ago, this crater was created by nature itself.

大约一前，这个火山口自然形成。

And then waiting for what felt like millions of years.

假装它等了几百。

And they think that happened roughly 200,000 years ago.

他们认为那大概发生在20前。

The strip of land, known as the Isthmus of Panama, was formed about 3.5 million years ago.

巴拿马地峡形成于350前。

But what about 10,000 years in the future?

但未来一后呢？

At 25 million years is a really long time.

2500 是很长的时间。

We have no idea what was happening 50,000 years ago.

我们并不知道5前发生了什么。

50,000 years ago, conditions were much harsher.

5 前，情况要恶劣得多。