The motion of a pendulum rocks this device so that it catches and then releases each tooth of the escape wheel, in turn allowing it to turn a precise amount.

钟摆的运动使这个装置晃动，如此一来这个装置能抓住擒纵轮的每一个齿，随后又将其释放，因而使其精确转动一段距离。

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No amount of cleaning will remove the severe staining left by tetracycline or systemic disease because these pigments lie inside the tooth; you'll have to take more aggressive measures against these.

不过洗牙次数再多也不能去除由于四环素或系统性疾病导致的牙齿深度着色，因为这些色素已进入你的牙齿内部，你需要采取更加积极地措施来对付它们。

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ScienceDaily (Sep. 6, 2009) - it's been a mystery: how can our teeth withstand such an enormous amount of pressure, over many years, when tooth enamel is only about as strong as glass?

科学日报(2009年9月6日)——当牙齿上的牙釉质大约只有玻璃般强硬时，我们的牙齿这么多年来是怎样经受住一个如此巨大的压力的？

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He said there were also "major areas of challenge" including disappointing breast feeding rates, large variations in preventable tooth decay in children, high death rates from lung diseases and a large amount of preventable cancers and cardiovascular disease.

BBC: Guernsey health profile released