新概念英语 学英语,练听力,上听力课堂! 注册 登录
> 新概念英语 > 新概念英语mp3 > 新概念英语第四册(美音版) >  第7课

新概念英语第四册(美音版)Bats

所属教程:新概念英语第四册(美音版)

浏览:

随身学
扫描二维码方便学习和分享

http://www.viz2016.com/lesson/shi0529/0000/46/7.mp3
http://www.viz2016.com/statics/js/2012

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 utilitarian 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 strictly utilitarian role.
To get a full appreciation 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 obstruction, the longer time will elapse for the return of the echo. A sound made by tapping on the hull of a ship will be reflected from the sea bottom, and by measuring the time interval 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 apparatus, 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, cod, or other well-known fish, by the pattern of its echo.

It has been found that certain bats emit squeaks and by receiving the echoes, they can locate and steer clear of obstacles -- or locate flying insects on which they feed. This echo-location in bats is often compared with radar, 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
squeak
n. 尖叫声

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?;厣祷厮檬奔渚驮匠?。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??捎肜状锵啾冉?,其原理是相似的。

1
我们正在学习的是新概念美音版,
传统版本(英式发音)的音频音频播放

2
本课的视频讲解:点击观看

全部:新概念英语第四册视频

 

相关文章
“新概念”介绍
学英语为什么要选新概念?
新概念第4册——体味英语的精髓
为什么专家提倡背诵新概念

相关下载
音频和文本下载,请看播放器右侧。
新概念英语第二册电子书下载:新概念第四册pdf电子书

更多新概念文本类资料下载

学习交流

新概念学习交流:http://www.viz2016.com/forum-79-1.html
下载录音软件:http://www.viz2016.com/thread-11915-1-1.html

内容来自 听力课堂网:http://www.viz2016.com/show-5046-925-1.html
用手机学英语,请加听力课堂微信公众号:tingclass123
用户搜索

疯狂英语 英语语法 新概念英语 走遍美国 四级听力 英语音标 英语入门 发音 美语 四级 新东方 七年级 赖世雄 zero是什么意思

                        1. 247881502 2018-01-21
                        2. 5045891501 2018-01-21
                        3. 313631500 2018-01-21
                        4. 2076671499 2018-01-20
                        5. 635781498 2018-01-19
                        6. 6781391497 2018-01-19
                        7. 2547851496 2018-01-19
                        8. 6645161495 2018-01-18
                        9. 6668371494 2018-01-18
                        10. 2778821493 2018-01-18
                        11. 9739831492 2018-01-17
                        12. 5983621491 2018-01-17
                        13. 8471911490 2018-01-16
                        14. 1388891489 2018-01-16
                        15. 4662891488 2018-01-15
                        16. 836291487 2018-01-15
                        17. 1952911486 2018-01-14
                        18. 3194311485 2018-01-14
                        19. 8495401484 2018-01-14
                        20. 5059431483 2018-01-13