One of the surprising findings from the new study, published Monday in the journal Archives of Internal Medicine, was just how little it took to knock down defenses against the common cold.

新研究中一项令人吃惊的发现，发表在周一的《内科医学档案杂志》， 即睡眠不足会让感冒抵抗力降到很低。

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Happiness is to come home and knock on the door, rather than reach out and touch the cold key.

幸福是回到家后敲门，而不是伸手去摸那冰冷的钥匙。

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It drew strength from the not so-young people who braved the bitter cold and scorching heat to knock on doors of perfect strangers.

力量来自不是很年轻的人，他们冒着严寒酷暑，敲开陌生人的家门进行宣传。

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It drew strength from the not-so-young people who braved the bitter cold and scorching heat to knock on doors of perfect strangers, and from the millions of Americans who volunteered and organized and proved that more than two centuries later a government of the people, by the people, and for the people has not perished from the Earth.

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Trays of cold cuts and cheese seem to arrive with every knock of the door.

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