Lesson 7 Bats蝙蝠

Bats

课文介绍 ^Introduction

• Bats are interesting animals. They are famous for their echo-location ability. ^{蝙蝠是有趣的动物，以回声定位能力著称。}
• Echo-location in bats is often compared with radar. ^{蝙蝠的回声定位常被拿来与雷达作比较。}

课文文体特点 ^{Text style features}

• 1. 倾向于将动词名词化（使文章更加正式）。^{Tendency to nominalize verbs (formal style)}
• 2. 倾向于使用被动语态（显得客观）。^{Tendency to use passive voice (objective tone)}

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 / every / both ^{部分否定结构}

act as / serve as / function as / be used as ^{当作……来使用}

have only to do ... to do ... ^{只须……就可以……}

• You have only to press the button to call the nurse. ^{你只要按下按钮就能叫护士。}
• You have only to click the link to download the software. ^{你只需点击链接就能下载软件。}
• We have only to turn to the example of the 1936 Olympics to know that sports can cause hatred. ^{我们只需借助1936年奥运会的例子就知道体育会导致仇恨。}

strictly ^{完全地，确切地}

• She is strictly a beauty. ^{她完全算得上是个美人。}
• It’s strictly a neutral organization. ^{这是一个完全中立的组织。}
• He spoke strictly according to the facts. ^{他完全根据事实发言。}

play / perform / act (the role / part of) ... ^{扮演……的角色}

play a ... role / part in ... ^{在……中起……作用}

• The river plays an important part in our lives. ^{那条河在我们的生活中起着重要作用。}
• The government should play a more prominent role in promoting human rights. ^{政府应在促进人权方面发挥更突出作用。}
• Chance discoveries play a large part in chemical industries. ^{偶然发现对化学工业起着重要作用。}

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

appreciation ^{理解（书面语）}

• There is a growing appreciation of the need for environmental reforms. ^{人们对环境改革的必要性越来越理解。}
• He showed little appreciation of her efforts. ^{他对她的努力几乎没有理解。}
• The manager has an appreciation of good design. ^{这位经理对优秀设计很有鉴赏力。}

名词化 ^写作技巧

turn to ^{求助于、借助于}

• When in doubt, turn to your teacher for help. ^{有疑问时，求助于老师。}
• Many people turn to music for comfort. ^{许多人借助音乐获得安慰。}
• In times of crisis, they turn to their friends. ^{在危机时，他们会求助朋友。}

Everyone knows that if he shouts in the vicinity of a wall or a mountainside, an echo will come back.

in the vicinity of ^{在……附近}

come back / bounce back / be reflected ^返回来

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

far / farther / further ^{远 / 更远 / 更深入}

• He lives far off in the mountains. ^{他住在山里很远的地方。}
• She walked further into the forest. ^{她走得更深入森林。}
• The farthest star can only be seen by telescope. ^{最远的星星只能用望远镜看到。}

比较句式 ^{越……越……}

• The harder they worked, the hungrier they became. ^{他们工作越努力，就越饿。}
• The more he gets, the more he wants. ^{他得到越多，就越贪心。}
• The stronger the magnet, the greater the number of lines of magnetic force. ^{磁铁越强，磁力线就越多。}

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.

be reflected ^被反射

• The sound will be reflected from the mountain. ^{声音会从山上反射回来。}
• Light is reflected from the surface of water. ^{光线从水面反射。}
• The sound was reflected from the walls. ^{声音被墙壁反射回来。}

sea bottom / sea bed / sea floor ^海床

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

倒装句 ^{强调句首状语}

• So was born the idea of democracy. ^{民主理念就这样诞生了。}
• So began a new era in science. ^{科学的新纪元由此开始。}
• So ended the long war. ^{漫长的战争就此结束。}

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

vary according to ^{因……而异}

• Prices vary according to demand. ^{价格随需求而变化。}
• Fees vary according to the course chosen. ^{学费因所选课程而异。}
• The results vary according to temperature. ^{结果因温度而不同。}

A shoal of fish will do this.

shoal of fish ^鱼群

• A shoal of fish swam past the boat. ^{一群鱼从船边游过。}
• We saw a shoal of fish shimmering in the sunlight. ^{我们看到一群鱼在阳光下闪闪发光。}
• The shoal of fish changed direction suddenly. ^{这群鱼突然改变了方向。}

So it is a comparatively simple step from locating the sea bottom to locating a shoal of fish.

comparatively ^相对地

• It is comparatively easy to learn. ^{这相对容易学习。}
• The test was comparatively simple. ^{考试相对简单。}
• Living costs here are comparatively low. ^{这里生活成本相对较低。}

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.

with experience ^{随着经验的积累}

• With experience, you will handle problems better. ^{随着经验的积累，你会更好地处理问题。}
• With time, things will get easier. ^{随着时间推移，事情会变得更容易。}
• With practice, your skills will improve. ^{通过练习，你的技能会提高。}

to tell if ^判断是否

• He tried to tell if she was lying. ^{他试图判断她是否在撒谎。}
• It is hard to tell if the news is true. ^{很难判断这消息是否真实。}
• We need to tell if the system is working properly. ^{我们需要判断系统是否正常运作。}

by ^根据

• He judged the distance by eye. ^{他凭目测判断距离。}
• We can estimate age by appearance. ^{我们可以根据外貌估算年龄。}
• They decided by voting. ^{他们通过投票决定。}

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.

emit ^{放射，发射}

• The factory emits smoke into the air every day.^{工厂每天向空气中排放烟雾。}
• Radioactive materials emit radiation.^{放射性物质会释放辐射。}
• He emitted a loud sigh of relief.^{他松了一口气。}

steer clear of ^{避开，躲开}

• We tried to steer clear of political issues.^{我们尽量避免涉及政治问题。}
• I steered clear of the main roads where I might be recognized.^{我避开了可能被认出的主干道。}
• He always steers clear of trouble.^{他总是远离麻烦。}

feed on ^以…为食

• Cows feed on hay.^{奶牛以干草为食。}
• Deer feed on grass and leaves.^{鹿吃草和树叶。}
• These birds feed on small insects.^{这些鸟以小昆虫为食。}

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

compare A with / to B ^{将A与B比较}

• People often compare the heart to a pump.^{人们常把心脏比作泵。}
• Let's compare our results with theirs.^{让我们把结果和他们的比较一下。}
• He compared her voice to music.^{他把她的声音比作音乐。}

名词 + 介词 + 关系代词 ^{引导非限定性定语从句}

• He has two sons, one of whom died in the war.^{他有两个儿子，其中一个死于战争。}
• The speaker posed four questions, the answers to which proved very illuminating.^{演讲者提出了四个问题，其答案被证明非常有启发性。}
• The most valuable find was the ship’s log book, parts of which were still readable.^{最有价值的发现是船舶日志，其中一部分仍然可以阅读。}