Sneezing is a reflex, which means that it 's an uncontrollable physical response to an outside stimulus.

打喷嚏是一种反射，也就是说它是一种生理对外界环境的反应，不可控制。

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Stress comes from the way we think and react to outside stimulus, so people with anxious tendencies will react in a more fearful way than their calmer counterparts.

压力来自于我们的思维方式和外界刺激的反应，因此具有焦虑倾向的人，他们对于压力的反应往往显得更加恐惧，这是不同于那些冷静的人群的。

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It's a great time for physical exercise because we have high body temperature, the fastest reaction to an outside stimulus, and the greatest muscle strength and cardiorespiratory efficiency.

这时是运动的最佳时机，因在体温最高的状态下，我们对外在刺激反应最快，肌力最强，心肺功能也最棒。

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Deprived of any outside sensory stimulus they were hyper-alert to the sight of young women from the outside.

BBC: Louis Theroux goes to the Miami mega-jail

Unlike rich countries, this argument goes, Latin America may gain more in the medium term by defending its hard-won fiscal stability and relying on the outside world for stimulus.

ECONOMIST: Latin America's economies