The simple truth is that there is an optimum rate of replacement, a best time for replacement.

道理很简单，厂房、设备都有最适当的折旧率，也就是最佳的更新年限。

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Resistance to mainstay antimicrobials is occurring at a rate that outpaces the development of replacement drugs.

主要抗菌素耐药性的出现速度超过了研制替代药物的速度。

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the fertility rate of half the world is now 2.1 or less—the magic number that is consistent with a stable population and is usually called “the replacement rate of fertility”.

世界上一半的地区，生育率仅为2.1%，甚至更低。 这一比率通常被称作“生育替代率”，标志着人口数量的稳定。

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The American fertility rate is around the replacement rate of 2.1, compared with 1.4 for Germany and Italy, where populations are in decline.

ECONOMIST: The retired are always supported by their children

But Phillip Watts, head of exploration and production, boldly reported a three-year average replacement rate of 102%.

FORBES: Shell Shocked

Africa has even higher TFRs, with many of its countries between 4 and 7, far higher than the replacement rate of 2.1.

FORBES: Declining Populations Make Peaceful Neighbors