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新概念英语第四册Lesson 7 Bats

时间:2005-04-25 16:00来源:互联网 提供网友:yaopf   字体: [ ]
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Lesson 7
Bats
蝙蝠

First listen and then answer the following question.
听录音,然后回答以下问题。

In what way does echo-location in bats play an utilitarian1 role?

Not all sounds made by animals serve as language, and we have only to turn to that extraordinary discovery of echo-location in bats to see a case in which the voice plays a strictly2 utilitarian role.
To get a full appreciation3 of what this means we must turn first to some recent human inventions. Everyone knows that if he shouts in the vicinity of a wall or a mountainside, an echo will come back. The further off this solid obstruction4, the longer time will elapse for the return of the echo. A sound made by tapping on the hull5 of a ship will be reflected from the sea bottom, and by measuring the time interval6 between the taps and the receipt of the echoes, the depth of the sea at that point can be calculated. So was born the echo-sounding apparatus7, now in general use in ships. Every solid object will reflect a sound, varying according to the size and nature of the object. A shoal of fish will do this. So it is a comparatively simple step from locating the sea bottom to locating a shoal of fish. With experience, and with improved apparatus, it is now possible not only to locate a shoal but to tell if it is herring, cod8, or other well-known fish, by the pattern of its echo.
It has been found that certain bats emit squeaks10 and by receiving the echoes, they can locate and steer11 clear of obstacles -- or locate flying insects on which they feed. This echo-location in bats is often compared with radar12, the principle of which is similar.
MAURICE BURTON Curiosities of animal life

New words and expressions生词和短语
bat
n. 蝙蝠
strictly
adv. 明确地
utilitarian
adj.实用的
appreciation
n. 理解
elapse
v. 障碍物
hull
n. 消逝
interval
n. 船体
receipt
n. 间隔
apparatus
n. 收到
shoal
n. 仪器
herring
n. 鱼群
cod
n. 鳕鱼
squeak9
n. 尖叫声

参考译文
动物发出的声音不都是用作语言交际。我们只要看一看蝙蝠回声定位这一极不寻常的发现,就可以探究一下声音在什么情况下有绝对的实用价值。
要透彻理解这句话的意义,我们应先回顾一下人类最近的几项发明。大家都知道,在墙壁或山腰附近发出的喊声,就会听到回声。固体障碍物越远。回声返回所用时间就越长。敲打船体所发了的声音会从海底传回来,测出回声间隔的时间,便可算出该处海洋的深度。这样就产生了目前各种船舶上普遍应用的回声探测仪。任何固体者反射声音,反射的声音因物体的大小和性质的不同而不同。鱼群也反射声音。从测定海深到测定鱼群,这一进展比较容易。根据经验和改进了的仪器,不仅能够确定鱼群的位置,而且可以根据鱼群回声的特点分辨出是鲱鱼、鳕鱼,这是人们所熟悉的其他鱼。
人们发现,某些蝙蝠能发出尖叫声,并能通过回声来确定并躲开障碍物,或找到它们赖以为生的昆虫。蝙蝠这种回声定位常常可与雷达相比较,其原理是相似的。
 


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1 utilitarian THVy9     
adj.实用的,功利的
参考例句:
  • On the utilitarian side American education has outstridden the rest of the world.在实用方面美国教育已超越世界各国。
  • A good cloth coat is more utilitarian than a fur one.一件优质的布外衣要比一件毛皮外衣更有用。
2 strictly GtNwe     
adv.严厉地,严格地;严密地
参考例句:
  • His doctor is dieting him strictly.他的医生严格规定他的饮食。
  • The guests were seated strictly in order of precedence.客人严格按照地位高低就座。
3 appreciation Pv9zs     
n.评价;欣赏;感谢;领会,理解;价格上涨
参考例句:
  • I would like to express my appreciation and thanks to you all.我想对你们所有人表达我的感激和谢意。
  • I'll be sending them a donation in appreciation of their help.我将送给他们一笔捐款以感谢他们的帮助。
4 obstruction HRrzR     
n.阻塞,堵塞;障碍物
参考例句:
  • She was charged with obstruction of a police officer in the execution of his duty.她被指控妨碍警察执行任务。
  • The road was cleared from obstruction.那条路已被清除了障碍。
5 hull 8c8xO     
n.船身;(果、实等的)外壳;vt.去(谷物等)壳
参考例句:
  • The outer surface of ship's hull is very hard.船体的外表面非常坚硬。
  • The boat's hull has been staved in by the tremendous seas.小船壳让巨浪打穿了。
6 interval 85kxY     
n.间隔,间距;幕间休息,中场休息
参考例句:
  • The interval between the two trees measures 40 feet.这两棵树的间隔是40英尺。
  • There was a long interval before he anwsered the telephone.隔了好久他才回了电话。
7 apparatus ivTzx     
n.装置,器械;器具,设备
参考例句:
  • The school's audio apparatus includes films and records.学校的视听设备包括放映机和录音机。
  • They had a very refined apparatus.他们有一套非常精良的设备。
8 cod nwizOF     
n.鳕鱼;v.愚弄;哄骗
参考例句:
  • They salt down cod for winter use.他们腌鳕鱼留着冬天吃。
  • Cod are found in the North Atlantic and the North Sea.北大西洋和北海有鳕鱼。
9 squeak 4Gtzo     
n.吱吱声,逃脱;v.(发出)吱吱叫,侥幸通过;(俚)告密
参考例句:
  • I don't want to hear another squeak out of you!我不想再听到你出声!
  • We won the game,but it was a narrow squeak.我们打赢了这场球赛,不过是侥幸取胜。
10 squeaks c0a1b34e42c672513071d8eeca8c1186     
n.短促的尖叫声,吱吱声( squeak的名词复数 )v.短促地尖叫( squeak的第三人称单数 );吱吱叫;告密;充当告密者
参考例句:
  • The upper-middle-classes communicate with each other in inaudible squeaks, like bats. 那些上中层社会的人交谈起来象是蚊子在哼哼,你根本听不见。 来自辞典例句
  • She always squeaks out her ideas when she is excited. 她一激动总是尖声说出自己的想法。 来自互联网
11 steer 5u5w3     
vt.驾驶,为…操舵;引导;vi.驾驶
参考例句:
  • If you push the car, I'll steer it.如果你来推车,我就来驾车。
  • It's no use trying to steer the boy into a course of action that suits you.想说服这孩子按你的方式行事是徒劳的。
12 radar kTUxx     
n.雷达,无线电探测器
参考例句:
  • They are following the flight of an aircraft by radar.他们正在用雷达追踪一架飞机的飞行。
  • Enemy ships were detected on the radar.敌舰的影像已显现在雷达上。
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TAG标签:   新概念  第四册
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