几个世纪以来，人类一直试图利用太阳的光作为可靠的能源。

Humanity has been trying to use the sun's light as a reliable source of energy for centuries.

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几个世纪以来，人类过度砍伐树木及过度集约耕作，一直在破坏环境。

Humans have been damaging the environment for centuries by overcutting trees and farming too intensively.

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在过去的一个世纪里，人类对淡水的使用以超过人口增长率两倍的速度增长。

Over the past century, human use of fresh water has increased at more than double the rate of population growth.

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Nevertheless, our knowledge of the earliest stages of human civilization was quite limited for many centuries.

然而，几个世纪以来,我们对人类最早时期文明,的认知是很有限的。

耶鲁公开课 - 旧约导论课程节选

One of the other things that happened during the twentieth century is that human life expectancy increased dramatically, people started living a lot longer.

在二十世纪发生的另一大变化是,人类的寿命预期显著增长了,人们活的更久了

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Now, in some time in that period of the Dark Ages, and Hanson would suggest, I think, probably around the eighth century is the greatest transition.

有时候在黑暗时代,我认为汉森同样会表明,大概在八世纪,人类历史经历了最伟大的转变

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