Not all sounds made by animals serve as language, and we have only to turn to that extraordinary discovery of echolocation (回聲定位) in bats to see a case in which the voice plays a strictly practical role.

To get a full appreciation of what this means we must turn first to some recent human inventions. Everyoneknows that if he shouts near a wall or a mountainside, an echo will come back. The further off this solid obstacle, the longer time it will take for the return of the echo. A sound made by tapping on the main body of a ship will be reflected from the sea bottom, and by measuring the time interval between the taps andthe receipt of the echoes the depth of the sea at that point can be calculated. So was born the echo-sounding equipment, 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 fromlocating the sea bottom to locating a shoal of fish. With experience, and with improved equipment, it is now possible not only to locate fish but to tell if it is herring, cod, or other well-known fish, by the pattern of its echo.

A few years ago it was found that certain bats emit squeaks (吱吱聲) and by receiving ’he echoes they could locate and steer clear of obstacles--or locate flying insects on which they feed. This echolocation in bats is often compared with radar, the principle of which is similar.

練習(xí)題：

Choose correct answers to the question:

1.The main purpose of this passage is to ______.

A. describe that animals can make different sounds

B. prove that animals’ voices can play practical roles

C. inspire the readers to make more inventions

D. startle the readers with some shocking facts

2. The discovery of echolocation may help with all of the following EXCEPT

A. measuring the depth of the sea

B. distinguishing different kinds of fish

C. improving the functions of radar

D. varying the size and nature of an object

3. By saying "A shoal of fish will do this"(Lines 6-7, Para. 2), the author means ________.

A. only one special kind of fish can reflect sounds

B. only one special kind of fish can be used to help locate a ship

C. a large group of fish can reflect sounds

D. a large group of fish can be used to help locate a ship

4. As it is discussed in the passage, the squeaks of bats can be functionally compared with ________.

A. human languages

B. a mountainside

C. a shoal of fish

D. taps on a ship

5. Which of the following statements can be inferred from the passage?

A. Animals are more intelligent than humans.

B. Humans are more intelligent than animals.

C. Animals are often compared with human inventions.

D. Humans are often inspired by animals.

參考答案及解析

1.[B] 主旨大意題。文章第1段就點(diǎn)明主題，明確指出以蝙蝠為例，動(dòng)物發(fā)出的聲音有實(shí)際作用，只有B可以概括文章的這個(gè)寫作目的。

2.[C] 事實(shí)細(xì)節(jié)題。本題考査列舉處，可用排除法解答。A、B、C在文中都有相關(guān)提及。D利用第2段中的varying制造干擾。在原文中，指的是回聲因障礙物的不同而不同，而D偷換概念、曲解文意，D中的varying為及物動(dòng)詞，意為“改變”,顯然不可能是回聲定位的發(fā)現(xiàn)帶來的功效。

3.[C] 詞義推斷題。本題考查對(duì)shoal的詞義推測及代詞this的理解。依據(jù)第2段最后幾句話,可推測出a shoal of fish指的是“海里的一群魚”;this則是指上一句提到的“任何固體都可以反射聲音”，因此這句話表明一大群魚就能像一個(gè)固體一樣反射聲音。

4.[D] 推理判斷題。根據(jù)最后一段可知，蝙蝠發(fā)出吱吱聲可以探測障礙物的距離，而第2段也指出輕敲船體可測知海底的距離，因此在功能上,D與蝙蝠的吱吱聲相同。A中的human languages在文中未提到;B和C在文中各自的例子中充當(dāng)?shù)亩际钦系K物的角色，因此都不正確。

5.[D] 推理判斷題。文章先說動(dòng)物的回聲定位功能,再說到回聲定位探測儀的發(fā)明,由此可見，是動(dòng)物的某些能力啟發(fā)了人類的創(chuàng)造，因此只有D可從文中推測。文章并沒有從智力方面比較人類和動(dòng)物，因此可以排除A 和B;盡管文章說到了蝙蝠和雷達(dá)的原理相似，但是C中的often一詞無據(jù)可循，且C的說法浮于表面，沒有說到重點(diǎn)，故排除。