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

But imagine doing crossword puzzles every day for 10 years, 1,000 years, a million years, a billion years, a trillion years.

但想象往后每天做填字游戏，玩上十年，一千年以至永远。

耶鲁公开课 - 死亡课程节选

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

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