首页
登录
职称英语
It is hard to track the blue whale, the ocean’s largest creature, which has
It is hard to track the blue whale, the ocean’s largest creature, which has
游客
2023-11-21
82
管理
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. [br] The passage is chiefly about ______.
选项
A、an effort to protect an endangered marine species
B、the civilian use of a military detection system
C、the exposure of a U.S. Navy top-secret weapon
D、a new way to look into the behavior of blue whales
答案
B
解析
本文首先以"tracking whales”为例说明“the Navy’s formerly top-secret system of underwater listening devices"对民用研究的用途,然后又讲到其他科学家利用这一系统来进行科学研究的例子,这一切都说明文章的主要内容是“the civilian use of a military detection system",所以,B 是正确答案。
转载请注明原文地址:https://tihaiku.com/zcyy/3207272.html
相关试题推荐
Certainlynocreatureintheseaisodderthanthecommonseacucumber.All
Outdooradvertisingprovidestheadvertiserwiththelargestcolourfuldisplay
Thelargestsystemservinge-mailmessengersistheInternet,a______ofmillio
Certainlynocreatureintheseaisodderthanthecommonseacucumber.All
_______NewYorkCityisAmerica’slargestcity,itisnotthecapitalofNewYo
Itishardtotrackthebluewhale,theocean’slargestcreature,whichhas
Itishardtotrackthebluewhale,theocean’slargestcreature,whichhas
Itishardtotrackthebluewhale,theocean’slargestcreature,whichhas
ThelibraryofcongressinWashington,D.C.,which【C1】______thelargestco
ThelibraryofcongressinWashington,D.C.,which【C1】______thelargestco
随机试题
Hisfatherwasputinto_____prison,andhehadtogoto_____prisontovisithim
Iamhonoredtobeheretoday,【L1】______HarvardatthiscelebrationoftheC
给定资料: 小福,11岁,五年级学生,父母都在佛山打工。大姐和三姐在读中学
小明对一张位图文件“风景.BMP”执行“复制、粘贴”命令.生成一个副本.再把副本
在现代国家的金融机构体系中,居于主体地位的是()。(2006年真题)A.中央
2013—2021年全国普通高校毕业生人数同比增速最慢的年份是:A.20
以下关于劳动效率定员法的表述,错误的是( )A.以手工操作为主的工种更适合采用
以个人好恶,兴趣爱好为联系纽带,具有强烈情感色彩的群体是()。A.非正式群体
一种商品价格上升,会引起另一种商品的需求随之下降,则这两种商品是()。A.
最新回复
(
0
)