但这条裂谷从1500万年前才开始发育。
But the rift did not begin to develop until around 15 million years ago.
我想象着千年万年前的故事。
这些起源于美国的第一批定居者万年前。
These have their origins in the first settlers of America ten thousand years ago.
早在七十多万年前，这里就有人类生存了。
As early as, years ago, there were already humans living here.
以你们的纪年法，这大约发生在50万年前。
即使是在20万年前，太多的冒险也可能让人丧命。
Well, even 200,000 years ago, too much risk-taking could get one killed.
他们认为这两个物种是在100多万年前分化出来的。
The two species are thought to have split over one million years ago.
一场在南极冰层中取回第一枚100万年前冰芯样品的比赛正式拉开了帷幕。
RACE is on to retrieve the first million-year-old sample from deep within Antarctica's ice.
这具来自4700万年前的珍贵化石是科学家们迄今为止所发现的最为完整的灵长类化石。
The 47-million-year-old prize is the most complete primate fossil ever found.
这具来自4700万年前的珍贵化石是科学家们迄今为止所发现的最为完整的灵长类化石。
The 47-million-year-old prize is the most complete primate fossil ever found.
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