Lesson 07 Bats

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In what way does echo-location in bats play a 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.

📝 文章大意

动物发出的声音并不都是语言，蝙蝠的回声定位就是一个声音纯粹起实用作用的例子。要理解这一点，可以先看人类的发明：对着墙或山喊话会听到回声，障碍物越远，回声返回得越慢。在船体上敲击，声音会从海底反射回来，测量敲击与回声之间的时间间隔就能算出海的深度，回声探测仪由此诞生。每个固体都会反射声音，鱼群也一样，所以从探测海底到探测鱼群只差一步，如今甚至能根据回声的模式判断出是鲱鱼还是鳕鱼。人们发现某些蝙蝠会发出尖叫声，靠接收回声来避开障碍物或捕捉飞虫，这种回声定位常被拿来和原理相似的雷达相比。

标题问题的答案：蝙蝠发出尖叫声，通过接收回声来确定方位，从而避开障碍物、找到作为食物的飞虫。

📚 核心单词

单词 音标 词性 含义 文中用法
echo-location /ˈekəʊ ləʊˌkeɪʃn/ n. 回声定位 echo-location in bats
utilitarian /ˌjuːtɪlɪˈteəriən/ adj. 实用的 a strictly utilitarian role
appreciation /əˌpriːʃiˈeɪʃn/ n. 理解，领会 get a full appreciation of
vicinity /vəˈsɪnəti/ n. 附近 in the vicinity of a wall
obstruction /əbˈstrʌkʃn/ n. 障碍物 this solid obstruction
elapse /ɪˈlæps/ v. （时间）流逝 the longer time will elapse
hull /hʌl/ n. 船体 the hull of a ship
reflect /rɪˈflekt/ v. 反射 be reflected from the sea bottom
interval /ˈɪntəvl/ n. 间隔 the time interval
receipt /rɪˈsiːt/ n. 收到 the receipt of the echoes
apparatus /ˌæpəˈreɪtəs/ n. 仪器，装置 the echo-sounding apparatus
shoal /ʃəʊl/ n. 鱼群 a shoal of fish
herring /ˈherɪŋ/ n. 鲱鱼 herring, cod
cod /kɒd/ n. 鳕鱼 herring, cod
emit /iˈmɪt/ v. 发出 emit squeaks
squeak /skwiːk/ n. 尖叫声 emit squeaks
steer clear of — phr. 避开 steer clear of obstacles
obstacle /ˈɒbstəkl/ n. 障碍 steer clear of obstacles

📖 难句解析

1. 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.

  • Not all ... 是部分否定：并非所有……都……
  • made by animals 是过去分词作后置定语，修饰 sounds；serve as = 起……的作用
  • have only to do ... to do = 只要……就能……
  • in which 引导定语从句修饰 a case
  • 译: 并不是所有动物发出的声音都起语言的作用。我们只要看一看蝙蝠回声定位这一非凡的发现，就能明白在某些情况下，动物的叫声纯粹是起实用作用的。

2. To get a full appreciation of what this means we must turn first to some recent human inventions.

  • To get ... 是不定式作目的状语
  • appreciation 在这里是”充分理解”，不是”欣赏”或”感激”
  • what this means 是宾语从句，this 指上句所说的蝙蝠回声定位
  • 译: 要充分理解这句话的意思，我们必须先看一看人类最近的一些发明。

3. The further off this solid obstruction, the longer time will elapse for the return of the echo.

  • the + 比较级 ..., the + 比较级 ... = 越……越……
  • 前半句省略了 is：The further off this solid obstruction (is)
  • elapse 指时间流逝，主语是 time
  • 译: 障碍物越远，回声返回所需的时间就越长。

4. 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.

  • made by tapping on ... 是过去分词短语，修饰 sound
  • by measuring ... 是方式状语，修饰后面的 can be calculated
  • between A and B：A 是 the taps，B 是 the receipt of the echoes
  • 主句是被动语态：the depth ... can be calculated
  • 译: 敲击船体发出的声音会从海底反射回来，测出敲击声和收到回声之间的时间间隔，就能算出该处海水的深度。

5. So was born the echo-sounding apparatus, now in general use in ships.

  • 完全倒装句，正常语序是 So the echo-sounding apparatus was born；主语较长，所以放到后面
  • now in general use 是 apparatus 的补充说明；in general use = 普遍使用
  • 译: 回声探测仪就这样诞生了，现在已普遍用于船上。

6. Every solid object will reflect a sound, varying according to the size and nature of the object.

  • varying ... 是现在分词短语，逻辑主语是被反射的声音，表示声音会随物体而变化
  • according to = 根据；nature 在这里是”性质”
  • 译: 每个固体都会反射声音，反射的声音随物体的大小和性质而不同。

7. 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 is possible to do：it 是形式主语，真正的主语是两个不定式
  • not only to locate ... but (also) to tell ... 连接两个不定式
  • tell if ... 的 tell = 辨别，不是”告诉”
  • by the pattern of its echo 修饰 tell，表示凭什么来辨别
  • 译: 凭借经验和改进的仪器，现在不仅能确定鱼群的位置，而且能根据回声的特征辨别出是鲱鱼、鳕鱼，还是其他人们熟悉的鱼。

8. 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.

  • It has been found that ... = 人们发现，it 是形式主语
  • that 从句里有两个分句：certain bats emit squeaks 和 by receiving ..., they can ...
  • locate and steer clear of 共用宾语 obstacles
  • on which they feed 是定语从句修饰 insects，来自 feed on = 以……为食
  • 译: 人们发现，某些蝙蝠能发出尖叫声，通过接收回声，它们能确定障碍物的位置并避开障碍物，或者找到它们作为食物的飞虫。

9. This echo-location in bats is often compared with radar, the principle of which is similar.

  • be compared with = 与……相比
  • the principle of which 引导非限制性定语从句，= and its principle，which 指 radar
  • 译: 蝙蝠的回声定位常被拿来与雷达相比，两者的原理是相似的。