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
82
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
(1)Aftertakingabriefhiatustoweathertherecession,aninvasionofBritainbysomeofAmerica’sbest-knownretailbrands
A、Practical.B、Conventional.C、Novel.D、Unrealistic.DDr.Adams建议人们应该设立实际可行的目标(realisticandattainablegoals),然后就说有人有疯狂的想法——30天学
Googlemaybevaluedatmorethan$185billionandboastmillionsofusers,butthatdoesn’tmeantheInternetgiantisanymatc
(1)Onanypersonwhodesiressuchqueerprizes,NewYorkwillbestowthegiftoflonelinessandthegiftofprivacy.Itist
Inrecentyears,itisnotuncommonthatacollegedegreecannotearnacollegegraduateadecentjobwhileskilledworkersf
PassageTwoComplaintsandlawsuitscannotsolvetheproblemofoverregulation,onlyideascan,butforanindustrybuilton
Afterthedevastatingearthquake,the________armywasimmediatelycalledintoevacuatetheweakandinjured.
ManydeathsduringchildbirthcouldbepreventedbythefollowingmethodsEXCEPT______.
WhichoneofthefollowingisNOTmentionedinthellstofthemilitaryequipmenthandedover?
HeandIcontributedthe______sumsof$6and$4.
随机试题
08F钢中字母F表示()。
Keepondoingwhateveryouweredoing.Ididn’tmean______you.
如何进行医疗器械灭菌效果的监测?
A.边缘扩展阳性B.尼氏征阳性C.雷诺征阳性D.针刺反应阳性E.Wickham纹扁平苔藓的皮肤损害表面常有
中国再保险有限公司是中国人民保险公司领导下的股份制合营专业再保险公司,他是1981年9月在香港成立的。()
有机氯农药化学性质稳定,不易降解,在环境和食品上长期残留。()
Duringthetraditionalweddingceremony,the【C1】______couplepromiseeachotherlifelongdevotion.Yet,aboutoneoutoffourAm
主板是PC机的核心部件,在自己组装PC机时可以单独选购。下面关于目前PC机主板的叙述中,错误的是( )
与Applet生命周期相关的方法的数量是()。
GeneticallyModifiedFoods—FeedtheWorld?A)Ifyouwanttosparkaheateddebateatadinnerparty,bringupthetopicofgenet
最新回复
(
0
)