首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
The idea of a fish being able to produce electricity strong enough to light lamp bulbs-or even to run a small electric motor—is
The idea of a fish being able to produce electricity strong enough to light lamp bulbs-or even to run a small electric motor—is
admin
2011-01-02
66
问题
The idea of a fish being able to produce electricity strong enough to light lamp bulbs-or even to run a small electric motor—is almost unbelievable, but several kinds of fish are able to do this. Even more strangely, this curious power has been acquired in different ways by fish belonging to very different families.
Perhaps the most known are the electric rays, or torpedoes, of which several kinds live in warm seas. They possess on each side of the head,behind the eyes, a large organ consisting of a number of hexagonal-shaped cells rather like a honeycomb. The ceils are filled with a jelly-like substance, and contain a series of flat electric plates. One side, the negative side, of each plate, is supplied with very fine nerves, connected with a main nerve coming from a special part of the brain. Current gets through from the upper, positive side of the organ downward to the negative, lower side. Generally it is necessary to touch the fish in two places, completing the circuit,in order to receive a shock.
The strength of this shock depends on the size of fish, but newly-born ones only about 5 centimeters across can be made to light the bulb of a pocket flashlight for a few moments, while a fully grown torpedo gives a shock capable of knocking a man down, and,if suitable wires are connected, will operate a small electric motor for several minutes.
Another famous example is the electric eel. This fish gives an even more powerful shock. The system is different from that of the torpedo in that the electric plates run longitudinally and are supplied with nerves from the spinal cord. Consequently, the current passes along the fish from head to tail. The electric organs of these fish are really altered muscles and like all muscles are apt to tire, so they are not able to generate electricity for very long. People in some parts of South America who value the electric eel as food, take advantage of this fact by driving horses into the water against which the fish discharge their electricity. The horses are less affected than a man would be, and when the electric eels have exhausted themselves, they can be caught without danger.
The electric catfish of the Nile and of other African fresh waters has a different system again by which current passes over the whole body from the tail to the head. The shock given by this arrangement is not so strong as the other two, but is none the less unpleasant. The electric catfish is a slow,lazy fish, fond of gloomy places and grows to about 1 metre long; it is eaten by the Arabs in some areas.
The power of producing electricity may serve these fish both for defence and attack. If a large enemy attacks, the shock will drive it away ;but it appears that the catfish and the electric eel use their current most often against smaller fish, stunning them so that they can easily be overpowered.
Which of the following can produce the strongest shock?
选项
A、The electric eel.
B、The electric catfish.
C、The newly-born electric torpedoes.
D、The fully-grown electric ray.
答案
A
解析
由文章第四段中的“Another famous example is the electric eel.This fish gives an even more powerful shock.”可知。
转载请注明原文地址:https://kaotiyun.com/show/A4Hd777K
本试题收录于:
公共英语五级笔试题库公共英语(PETS)分类
0
公共英语五级笔试
公共英语(PETS)
相关试题推荐
TechnologyTransferinGermanyWhenitcomestotranslatingbasicresearchintoindustrialsuccess,fewnationscanmatchGerman
WhyWouldTheyFalselyConfess?Whyonearthwouldaninnocentpersonfalselyconfesstocommittingacrime?Tomostpeople,it
WhatisMarket?Thewordmarketisusedinanumberofways.Thereisastockmarketandautomobilemarket,aretailmarketfor
Successfulleadersdominateeventsratherthanreacttothem.
ImproveComputer-researchSkillsLikemanycollegestudents,JoseJuarezcarriesaroundapocket-sizedcomputerthatletshi
YouthEmancipationinSpainTheSpanishGovernmentissoworriedaboutthenumberofyoungadultsstilllivingwiththeirpa
IsThereaWaytoKeeptheBritain’sEconomyGrowing?1.Intoday’sknowledgeeconomy,nationssurviveonthethingstheydo
OntheTrialoftheHoneyBadgerOnarecentfieldtriptotheKalahariDesert,ateamofresearcherslearnalotmoreabout
OntheTrialoftheHoneyBadgerOnarecentfieldtriptotheKalahariDesert,ateamofresearcherslearnalotmoreabout
Wherecantheexpression"lameduck"beheard?
随机试题
洋务运动时期国内最大的造船厂是()。
钢管可分为有缝钢管和无缝钢管。
三大类营养物质的消化产物大部分被吸收的部位()
A.急性粟粒性肺结核B.急性空洞型肺结核C.局灶型肺结核D.干酪性肺炎E.广泛性肺结核属于血源播散性肺结核的是
关于散剂的描述正确的是
战略投资者不得参与首次公开发行股票的初步询价和累计投标询价,并应当承诺获得本次配售的股票持有期限不少于()个月,持有期自本次公开发行的股票上市之日起计算。
事业单位随买随用的零星办公用品应作为存货核算。()
简述侵害名誉权的构成要件。
电子商务是指通过数字通信进行商品和服务的买卖以及资金的转账。根据上述定义,下列属于电子商务的是()。
NarratorListentotheconversationbetweenastudentandtheclubsecretary.Nowgetreadytoanswerthequestions.You
最新回复
(
0
)