英语听力文摘 English Digest 268、你为何要睡觉？

　　You Snooze or You Lose
几乎每个人在忙碌了一天之后，都要香香地睡上一觉。当然也有活了一辈子不 睡觉的人，但那是极个别的。人要睡觉是一种生理反应，是大脑神经活动的一部分， 是大脑皮质内神经细胞继续兴奋之后产生了抑制的结果。当抑制作用在大脑皮质内 占优势的时候，人就会睡觉。 人们在生活中，有工作，有休息，在神经活动中，有兴奋，有抑制。抑制是为了保护神经细胞，以便让它重新兴奋，让人们继续工作。
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 mundane¹ 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 fulfill²: 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 entirely³ lost, and we don’t have the smelling or hearing acuity⁴ 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 lapsed⁵ into silence when the schoolteacher came into the classroom.
当老师走进教室时，学生们安静下来。
(2)stay put 留在原处不动
The policeman ordered him to stand up and stay put.
警察命令他站起来别动。
(3)on the prowl 徘徊
Today there is still local demand for banking⁶ staff: Tesco, a retailer⁷ expanding into the sector⁸, is on the prowl.
现在还有本地仍有对银行工作人员需求：一家扩张到银行业部门的零售商特易购在寻求机会。

1 mundane   

adj.平凡的；尘世的；宇宙的

参考例句：

• I hope I can get an interesting job and not something mundane.我希望我可以得到的是一份有趣的工作，而不是一份平凡无奇的。
• I find it humorous sometimes that even the most mundane occurrences can have an impact on our awareness.我发现生活有时挺诙谐的，即使是最平凡的事情也能影响我们的感知。

2 fulfill   

vt.履行，实现，完成；满足，使满意

参考例句：

• If you make a promise you should fulfill it.如果你许诺了，你就要履行你的诺言。
• This company should be able to fulfill our requirements.这家公司应该能够满足我们的要求。

3 entirely   

ad.全部地，完整地；完全地，彻底地

参考例句：

• The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
• His life was entirely given up to the educational work. 他的一生统统献给了教育工作。

4 acuity   

n.敏锐，（疾病的）剧烈

参考例句：

• We work on improving visual acuity.我们致力于提高视觉的敏锐度。
• The nurse may also measure visual acuity.护士还可以检查视敏度。

5 lapsed   

adj.流失的，堕落的v.退步( lapse的过去式和过去分词 )；陷入；倒退；丧失

参考例句：

• He had lapsed into unconsciousness. 他陷入了昏迷状态。
• He soon lapsed into his previous bad habits. 他很快陷入以前的恶习中去。 来自《简明英汉词典》

6 banking   

n.银行业，银行学，金融业

参考例句：

• John is launching his son on a career in banking.约翰打算让儿子在银行界谋一个新职位。
• He possesses an extensive knowledge of banking.他具有广博的银行业务知识。

7 retailer   

n.零售商(人)

参考例句：

• What are the retailer requirements?零售商会有哪些要求呢？
• The retailer has assembled a team in Shanghai to examine the question.这家零售商在上海组建了一支团队研究这个问题。

8 sector   

n.部门，部分；防御地段，防区；扇形

参考例句：

• The export sector will aid the economic recovery. 出口产业将促进经济复苏。
• The enemy have attacked the British sector.敌人已进攻英国防区。