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
It is hard to track the blue whale, the ocean’s largest creature, which has almost been killed off by commercial whaling and is
It is hard to track the blue whale, the ocean’s largest creature, which has almost been killed off by commercial whaling and is
admin
2010-01-15
35
问题
It is hard to track the blue whale, the ocean’s largest creature, which has almost been killed off by commercial whaling and is now listed as an endangered species. Attaching radio devices to it is difficult, and visual sightings are too unreliable to give real insight into its behavior.
So biologists were delighted early this year when, with the help of the Navy, they were able to track a particular blue whale for 43 days, monitoring its sounds. This was possible because of the Navy’s formerly top-secret system of underwater listening devices spanning the oceans.
Tracking whales is but one example of an exciting new world just opening to civilian scientists after the cold war as the Navy starts to share and partly uncover its global network of underwater listening system built over the decades to track the ships of potential enemies.
Earth scientists announced at a news conference recently that they had used the system for closely monitoring a deep-sea volcanic eruption for the first time and that they plan similar studies.
Other scientists have proposed to use the network for tracking ocean currents and measuring changes in ocean and global temperatures.
The speed of sound in water is roughly one mile a second--slower than through land but faster than through air. What is most important, different layers of ocean water can act as channels for sounds, focusing them in the same way a stethoscope does when it carries faint noise from a patient’ s chest to a doctor’ s ear. This focusing is the main reason why even relatively weak sounds in the ocean, especially low-frequency ones, can often travel thou- sands of miles.
The underwater listening system was originally designed ______.
选项
A、to trace and locate enemy vessels
B、to monitor deep-sea volcanic eruptions
C、to study the movement of ocean currents
D、to replace the global radio communications network
答案
A
解析
根据第三段的“…its global network of underwater listening system built over the decades to track the ships of potential enemies.”,可以看出这套系统最初是为了“trace and locate enemy vessels”而建立的,所以,A 符合题意。
转载请注明原文地址:https://kaotiyun.com/show/1GnK777K
0
专业英语四级
相关试题推荐
Self-discipline:theFoundationofProductiveLivingI.Issuestobenoticedatthethoughtofself-disciplineA.Troublesf
A、Theonemakingstrongreaction.B、Theonewhoislifeless.C、Theonefeelingsympathy.D、Theonewhoisalive.AChitra提到了一系列评判
MostWestAfricanlorriesarenotinwhatonewouldcallthefirstflushofyouth,andIhadlearntbybitterexperiencenott
FourreasonsthatrosyNovemberjobsreportwasevenbetterthanitseemed.It’simportantnottomaketoomuchoutofasingl
A、Enoughfund.B、Aclearaim.C、Everydoctor’sknowledgeofthisissue.D、Medicalaid.C
PeoplewhogrewupinAmericaandWesternEuropehavebecomeusedtotheideathattheWestdominatestheworldeconomy.Inf
Manymiddle-agedandelderlywomenareoftenseenparticipatingthepublicsquaredancinginanefforttoexerciseandsociali
A、Becausemainstreamlanguageneedschange.B、Becausecomputerscientistsdon’tusethesewords.C、BecausetheInternetisdevel
NearlytwothousandyearshavepassedsinceacensusdecreedbyCaesarAugustusbecomepartofthegreateststoryevertold.Man
USHigherEducationLurkingbehindthegleamingpromiseofeverywide-eyedfreshmanisadarkfactofUShighereducation:
随机试题
若在水中溶解KNO3和Na2SO4两种盐,形成不饱和溶液,则该体系的组分数为()。
对死亡率的描述正确的是
中药饮片贮存过程中,易粘连的饮片是
肺炎链球菌肺炎的抗菌治疗首选
妊娠合并重症肝炎的处理要点包括()
根据我国经济社会发展战略,我国要在()成为工业化基本实现、综合国力显著增强、国内市场总体规模位居世界前列的国家。
保荐机构应对在深圳证券交易所上市的上市公司披露的哪些情况发表独立意见()。Ⅰ.募集资金使用情况Ⅱ.委托理财Ⅲ.与合并范围内的子公司发生的关联交易Ⅳ.对合并范围内的子公司提供担保
企业对于合同利益相关者应承担的社会责任有()。
正式访问
Bythetimeyougraduate,we______inAustraliaforoneyear.
最新回复
(
0
)