英語聽力文摘 你為何要睡覺？
You Snooze or You Lose
幾乎每個人在忙碌了一天之后，都要香香地睡上一覺。當(dāng)然也有活了一輩子不 睡覺的人，但那是極個別的。人要睡覺是一種生理反應(yīng)，是大腦神經(jīng)活動的一部分， 是大腦皮質(zhì)內(nèi)神經(jīng)細(xì)胞繼續(xù)興奮之后產(chǎn)生了抑制的結(jié)果。當(dāng)抑制作用在大腦皮質(zhì)內(nèi) 占優(yōu)勢的時候，人就會睡覺。 人們在生活中，有工作，有休息，在神經(jīng)活動中，有興奮，有抑制。抑制是為了保護神經(jīng)細(xì)胞，以便讓它重新興奮，讓人們繼續(xù)工作。
It’s such a commonplace event that you probably never asked yourself why you sleep. But from a scientific point of view, this is far from a mundane matter — in fact, for sleep researchers, it’s one of the biggest unanswered questions in the field.
Stop and think about it for a second. Why should we sleep? Is it because we get tired? But we sleep every night, even when we have had plenty of rest.Furthermore, if you were designing an animal, would you have it (1)lapse into prolonged periods of unconsciousness every twenty-four hours? Shouldn’t that put it at a terrible disadvantage?
There are no doubt several different answers to this question, but let’s just consider one overall purpose sleep may fulfill: sleep as a survival strategy.
Human beings are “diurnal” creatures. That means we are normally active during daylight hours, when our senses function most effectively. At night, humans do rather poorly: we can’t see objects well, our color vision is entirely lost, and we don’t have the smelling or hearing acuity of other animals. So it actually does makes sense to have us (2)stay put during the dangerous period when “nocturnal,” or night-waking, animals are (3)on the prowl. And one sure way to make sure we don’t stumble around and get lost or eaten is to have us immobilized for seven or eight hours, rising again only when the light is back and our survival chances are better.
It’s not the only reason we sleep; but in terms of evolution, it may have been one of the first reasons — perhaps even the most important one.
Notes:
(1)lapse into 陷入
The pupils lapsed into silence when the schoolteacher came into the classroom.
當(dāng)老師走進教室時，學(xué)生們安靜下來。
(2)stay put 留在原處不動
The policeman ordered him to stand up and stay put.
警察命令他站起來別動。
(3)on the prowl 徘徊
Today there is still local demand for banking staff: Tesco, a retailer expanding into the sector, is on the prowl.
現(xiàn)在還有本地仍有對銀行工作人員需求：一家擴張到銀行業(yè)部門的零售商特易購在尋求機會。
