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 generate electricity strong enough to light lamp bulbs--or even to run a small electric motor--
The idea of a fish being able to generate electricity strong enough to light lamp bulbs--or even to run a small electric motor--
admin
2013-02-03
30
问题
The idea of a fish being able to generate 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 best 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 cells are filled with a jelly-like substance, and contain a series of fiat 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 passes from the upper, positive side of the organ downwards 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 the fish, but newly born ones only about 5 centimetres 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 produce electricity for very long.
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.
For answers 51-55, mark
Y(for YES) if the statement agrees with the information given in the passage;
N (for NO) if the statement contradicts the information, given in the passage;
NG(for NOT GIVEN) if the information is not given in the passage.
The electric fish produce electricity mainly for ______.
选项
答案
(defence and) attack
解析
由最后一段第一句“The power of producing electricity may serve these fish both for defence and attack”可知答案为defence and attack。
转载请注明原文地址:https://kaotiyun.com/show/FWyK777K
本试题收录于:
A类竞赛(研究生)题库大学生英语竞赛(NECCS)分类
0
A类竞赛(研究生)
大学生英语竞赛(NECCS)
相关试题推荐
Somepeoplemaychoosetoliveonwaterforthepleasureandenjoymentofhavingahomethatisdifferentfromthehomesofmost
SituatedattheheartofBeijing,thePalaceMuseumisapproachedthroughtheGateofHeavenlyPeace(Tian’anmen).Becauseofit
SituatedattheheartofBeijing,thePalaceMuseumisapproachedthroughtheGateofHeavenlyPeace(Tian’anmen).Becauseofit
Thetermcultureshockwasintroducedforthefirsttimein1958todescribetheanxietyproducedwhenapersonmovestoacompl
Aswecanwaitnolongerforthedeliveryofyourorder,wehaveto______it.
Formanypeopletoday,readingisnolongerrelaxation.Tokeepuptheirwork,theymustreadletters,reports,tradepublication
Formanypeopletoday,readingisnolongerrelaxation.Tokeepuptheirwork,theymustreadletters,reports,tradepublication
DevelopingEnvironmentalManagementStrategiesStrongandsustainableeconomicactivitydependsonhealthyenvironmentalman
CanadianauthoritiesrelayedthatsuspiciontotheU.S.CoastGuard,whichdispatchedacuttertointerceptthevessel.Aftera
Inafamilywheretherolesofmenandwomenarenotsharplyseparatedandwheremanyhouseholdtasksaresharedtoagreateror
随机试题
螺旋式课程的最初倡导者是()
小脑扁桃体下疝畸形颅底凹陷症
消防安全组织人员基本分为消防安全责任人、消防安全管理人、专(兼)职消防管理人员、自动消防系统操作人员、部门消防安全负责人等。下列有关消防安全组织人员说法中,不正确的是()。
流动性陷阱是指()。
企业对投资性房地产,无论采用何种计量模式,均应计提折旧或进行摊销。()
下列各项中,应计入工业企业产品成本的是()。
下列各项中,诉讼时效为2年的事项是()。
企业接受捐赠设备时发生的有关费用,应单独核算而不能计入固定资产价值。()
从铁腕规范党内生活,到铁面问责严格执纪;从亮短揭丑的民主生活会,到重拳破除各种潜规则。党的十八大以来,守底线、讲原则、重法治成为新常态,这有利于广大党员()。
某县政府作出有关规范该县蔬菜市场秩序的决定,这一决定属于()。
最新回复
(
0
)