Eighty million years ago, dinosaurs ruled the earth.

八千万年前，地球是恐龙的天下。

《牛津词典》

South America and Africa separated 200 million years ago.

南美洲和非洲于2亿年前分离。

《牛津词典》

South America separated from Africa 200 million years ago.

2亿年前南美洲和非洲分离。

《牛津词典》

The story of the Sierra Nevada Mountains and the area that is Yosemite National Park begins about 500 million years ago.

VOA: special.2009.01.07

Suppose the planet were hit by a comet-- this happened--something like this happened sixty-five million years ago, so it could happen again.

假设这个星球被一颗彗星击中-,这样的事，大约六千五百万年前,发生过，所以它还可能再发生。

耶鲁公开课 - 金融市场课程节选

This Cambridge History of Food talks about three separate primary phases in human food evolution: one beginning a million and a half years ago, another about 700,000 years ago, and then the 10,000 year ago one that I talked about just a moment ago.

剑桥饮食史》描述了,人类饮食结构演化过程中的三个不同阶段,其一,始于一百五十万年前,其二,距今约七十万年,其三,距今一万年,我们刚讨论过了

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

All of the fossils date back to 183 million years ago during the Jurassic period.

BBC: Museum of Somerset marine insect fossil study starts

The last one happened 65 million years ago when a large asteroid crashed into the Earth.

BBC: Leaving our mark: What will be left of our cities?

Finds from Java suggest early humans reached South-East Asia by 1.6 million years ago.

BBC: 'Peking Man' older than thought