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
Even in fresh water sharks hunt and kill. The Thresher shark, capable of lifting a small boat out of the water, has been sighted
Even in fresh water sharks hunt and kill. The Thresher shark, capable of lifting a small boat out of the water, has been sighted
admin
2013-01-20
31
问题
Even in fresh water sharks hunt and kill. The Thresher shark, capable of lifting a small boat out of the water, has been sighted a mile inland on the Fowey River in Corn-wall. Killer sharks swim rivers to reach Lake Nicaragua in Central America; they average one human victim each year.
Sewage and garbage attract sharks inland. When floods carry garbage to the rivers they provide a rich diet which sometimes stimulates an epidemic of shark attacks. Warm water generally provides shark food, and a rich diet inflames the shark’s aggression.
In British waters sharks usually swim peacefully between ten and twenty miles off- shore where warm water currents fatten mackerel and pilchards for their food. But the shark is terrifyingly unpredictable. One seaman was severely mauled as far north as Wick in Scotland. Small boats have been attacked in the English Channel, Irish Sea and North Sea.
Most of the legends about sharks are founded in ugly fact. Even a relatively small shark--a 200 lb. Zambezi--can sever a man’s leg with one bite, Sharks have up to seven rows of teeth and as one front tooth is damaged or lost another moves forward to take its place. The shark never sleeps. Unlike most fish, it has no air bladder, and it must move constantly to avoid sinking. It is a primitive creature, unchanged for sixty million years of evolution. Its skin is without the specialized scales of a fish. Fully grown, it still has five pairs of separate gills like a three-week human embryo.
But it is a brilliantly efficient machine. Its skin carries nerve endings which can detect vibrations from fish moving several miles away. Its sense of smell, the function of most of its brain, can detect one p. art in 600,000 of tuna fish juice in water, or the blood of a fish or animal from a quarter of a mile away. It is colour blind, and sees best in deep water, but it can distinguish shapes and patterns of light and shade easily. Once vibrations and smell have placed its prey the shark sees well enough to home in by vision for the last fifty feet. The shark eats almost anything. It will gobble old tin cans and broken bottles as well as fish, animals and humans. Beer bottles, shoes, wrist watches, car number plates, overcoats and other sharks have been found in dead sharks. Medieval records tell of entire human corpses still encased in armour.
The United States military advice on repelling sharks is to stay clothed--sharks go for exposed flesh, especially the feet. Smooth swimming at the surface is essential. Frantic splashing will simply attract sharks, and dropping below the surface makes the swimmer an easy target.
If the shark gets close, then is the time to kick, thrash and hit out. A direct hit on the snout, gills, or eyes will drive away most sharks. The exception is the Great White shark. It simply kills you.
Why do sharks normally swim between ten and twenty miles off the coast of Britain?
选项
A、They prefer warm water to cold water.
B、They see best in deep water.
C、They are afraid of man.
D、That is where their food is.
答案
D
解析
本题的依据句是第三段第一句“In British waters sharks usually swim peacefully between ten and twenty miles offshore where warm water currents fatten mackerel and pilchards for their food.”从中可知,D项为正确答案。
转载请注明原文地址:https://kaotiyun.com/show/dY2O777K
0
考博英语
相关试题推荐
Writeacompositionofabout200wordsonthefollowingtopic.RemembertowriteyourcompositiononAnswerSheetII.
Tidesarecreatedmainlybythepullofthemoonontheearth.Themoon’spullcauseswaterintheoceanstobealittledeeper
HowtoDoFewer,BetterAnimalExperimentsForanationofpetlovers,Britainconductsasurprisingnumberofexperimentso
Advertiserstendtothinkbigandperhapsthisiswhythey’realwayscominginforcriticism.Theircriticsseemtoresentthem
ScienceFictioncanprovidestudentsinterestedinthefuturewithabasicintroductiontotheconceptofthinkingaboutpossibl
Somecultureshavecustomsthat_____theclothingfashionsofpeopleincertainsocialclasses.
Thinkaboutwhatwouldmakeyoureally,reallyhappy.Moremoney?Wrong.Smiling,well-adjustedkids?Wrongagain.Thefactisw
Whenitcomestotheslowingeconomy,EllenSperoisn’tbitinghernailsjustyet.Butthe47-year-oldmanicuristisn’tcutting,
Theroleofgovernmentinenvironmentalmanagementisdifficultbutinescapable.Sometimes,thestatetriestomanagetheresour
Theroleofgovernmentinenvironmentalmanagementisdifficultbutinescapable.Sometimes,thestatetriestomanagetheresour
随机试题
香港大学言语听觉科学系曾与南京师范大学教育科学学院合作,在江苏省苏南、苏北地区及南京市进行语言障碍儿童的调查,这次调查发生在哪一年()
A.神经纤维瘤病B.结肠腺瘤性息肉病C.视网膜母细胞瘤D.肾母细胞瘤WT1基因
癃闭的实证,选用下列哪组穴位( )。
下列哪项为阴虚火旺型心悸的主症
下列不属于中风的病理因素是()
( )是以货币形式编制施工项目在计划期内的生产费用、成本水平、成本降低率以及为降低成本所采取的主要措施和规划的书面方案,它是建立施工项目成本管理责任制、开展成本控制和核算的基础。
顺序数据的功能比分类数据要弱一些。()
下列关于“以剩余收益作为投资中心业绩评价标准优点”的表述中,正确的有()。
能直接与CPU交换信息的存储器是()。
BossesSay"Yes"toHomeWorkA)Risingcostsofofficespace,timelosttostressfulcommuting,andaslowrecognitionthatwork
最新回复
(
0
)