The "modernization theory", which centers on the Lipset thesis, went through three stages: rise, decline, and revival.

以利普塞特论文为中心的“现代化理论”经历了三个阶段：上升，下降和复兴。

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The amount of oxidative damage increases with age, and according to one theory of aging it is a major cause of the body's decline.

因氧化造成的损害随年龄增长，且根据一个关于衰老的理论说这是人体衰退的主要因素。

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In turn, many proponents of "peak oil" theory, the idea that the global rate of oil production has entered a terminal decline, have insisted that the cable confirms their view on resource scarcity.

相应地，许多“石油峰值理论”的支持者认为这封电报恰恰证实了他们关于资源短缺的观点。石油峰值理论认为，全球石油生产率已经进入了最后的衰减期。

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For example, if productivity falls, current returns decline, says the theory, so workers and firms choose to work less and take more leisure.

ECONOMIST: The causes of booms and busts

The theory is that reversing that decline before surgery may help patients be mobile and active afterwards.

BBC: Could fitness be key to cancer surgery success?

In theory, the region should provide it with boundless opportunities to offset the decline in its population.

ECONOMIST: Friends and neighbours