# 第四册 Lesson 7 Bats 蝙蝠

## 一、课文原文

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*

## 二、重点词汇详解

| 单词 | 音标 | 词性 | 释义 | 用法说明 |
|------|------|------|------|----------|
| echo-location | /ˈekəʊləʊˌkeɪʃn/ | n. | 回声定位 | 蝙蝠和海豚的声纳系统 |
| utilitarian | /ˌjuːtɪlɪˈteəriən/ | adj. | 功利的，实用的 | strictly utilitarian 严格的实用功能 |
| appreciation | /əˌpriːʃiˈeɪʃn/ | n. | 理解，欣赏 | get a full appreciation of 充分理解 |
| vicinity | /vɪˈsɪnɪti/ | n. | 附近，邻近 | in the vicinity of 在...附近 |
| elapse | /ɪˈlæps/ | v. | （时间）消逝 | time elapses 时间流逝 |
| obstruction | /əbˈstrʌkʃn/ | n. | 障碍物 | solid obstruction 实体障碍物 |
| hull | /hʌl/ | n. | 船体，船壳 | the hull of a ship 船体 |
| interval | /ˈɪntəvl/ | n. | 间隔 | time interval 时间间隔 |
| shoal | /ʃəʊl/ | n. | 鱼群 | a shoal of fish 一群鱼 |
| emit | /ɪˈmɪt/ | v. | 发出，射出 | emit squeaks 发出尖叫声 |
| squeak | /skwiːk/ | n./v. | 尖叫声，吱吱声 | 蝙蝠发出的超声波叫声 |
| steer | /stɪə/ | v. | 驾驶，引导 | steer clear of 避开 |
| herring | /ˈherɪŋ/ | n. | 鲱鱼 | 常见食用鱼 |
| cod | /kɒd/ | n. | 鳕鱼 | 常见食用鱼 |

## 三、语法知识点

### 1. 部分否定

> **Not all** sounds made by animals serve as language.

| 结构 | 含义 | 对比 |
|------|------|------|
| not all + 名词 | 并非所有...都 | all...not（同义，但不够正式） |
| not every + 单数名词 | 并非每个...都 | every...not |
| not both + 名词 | 并非两个...都 | both...not |

### 2. 倒装句

> **So was born** the echo-sounding apparatus...

- so + be动词 + 主语，表示"于是...诞生了"
- 完全倒装，强调结果

### 3. the + 比较级，the + 比较级

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

- 越...越...，与第3课相同句型
- 注意前后两部分都使用比较级

### 4. not only...but (also)... 并列递进

> ...**not only** to locate a shoal **but** to tell if it is herring, cod, or other well-known fish...

- 否定前移时需倒装：Not only is it possible to..., but it is also possible to...

## 四、重点句型分析

### 1. serve as 作为，充当

> Not all sounds made by animals serve as language.

- = function as, act as
- 仿写：This room serves as my study.

### 2. have only to 只需

> ...we have only to turn to that extraordinary discovery...

- = need only to, just have to
- 仿写：You have only to ask and he will help.

### 3. steer clear of 避开

> ...they can locate and steer clear of obstacles...

- = avoid, keep away from
- 仿写：Steer clear of trouble when you can.

### 4. turn to 求助于，转向

> ...we must turn first to some recent human inventions.

- turn to = refer to, look at
- 也可表示"求助于"：turn to sb. for help

## 五、课文翻译

并非动物发出的所有声音都充当语言，我们只需看看蝙蝠回声定位这一非凡的发现，就能看到声音发挥严格实用功能的一个实例。要充分理解这意味着什么，我们必须先来看看人类近期的一些发明。人人都知道，如果在墙壁或山坡附近大喊一声，就会有回声传来。实体障碍物越远，回声返回所需的时间就越长。敲击船体发出的声音会从海底反射回来，通过测量敲击和收到回声之间的时间间隔，就可以计算出该处海水的深度。回声探测仪就这样诞生了，如今在船上已被普遍使用。每个固体都会反射声音，反射的方式因物体的大小和性质而异。鱼群也会反射声音。因此，从定位海底到定位鱼群是一个相对简单的步骤。凭借经验和改进的设备，现在不仅能定位鱼群，还能通过回声的模式判断它是鲱鱼、鳕鱼还是其他知名鱼种。

人们发现，某些蝙蝠发出尖叫声，通过接收回声，它们能定位并避开障碍物——或者定位它们赖以为食的飞虫。蝙蝠的回声定位常被拿来与雷达相比，两者的原理相似。

## 六、语言点精讲

### 1. 写作手法：类比论证

- 先讲人类发明（回声探测仪），再讲蝙蝠的天生能力
- 由已知到未知的类比推理，使抽象概念变得易懂

### 2. 文化背景

- **回声探测仪（echo-sounding apparatus）**：第一次世界大战期间发明的声纳技术
- **雷达（radar）**：第二次世界大战期间发展的无线电探测技术，与蝙蝠回声定位原理相似

### 3. 修辞分析

- **部分否定开篇**：Not all...——精确表达，避免绝对化
- **类比过渡**：由人→由船→由鱼→由蝙蝠，层次递进
- **破折号补充**：-- or locate flying insects——用破折号补充蝙蝠回声定位的双重功能

## 七、课后练习要点

1. **理解题**：In what way does echo-location in bats play a utilitarian role?（实用功能：定位障碍物和猎物）
2. **语法题**：部分否定 not all 的多种表达与全部否定的区别
3. **词汇题**：区分 emit/transmit/reflect 的用法
4. **翻译练习**：the more...the more...句型的翻译

## 八、本课小结

本课以**蝙蝠回声定位**为主题，通过类比论证从人类声纳技术引出蝙蝠的天然能力。语法重点包括部分否定（not all）、倒装句（So was born...）、the more...the more比较句型、not only...but递进结构。写作手法上运用类比递进和部分否定开篇，是科普说明文的优秀范例。