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
Why don’t birds get lost on their long flights from one place to another? Scientists have puzzled over this question for many ye
Why don’t birds get lost on their long flights from one place to another? Scientists have puzzled over this question for many ye
admin
2014-10-11
69
问题
Why don’t birds get lost on their long flights from one place to another? Scientists have puzzled over this question for many years. Now they’re beginning to fill in the blares.
Not long ago, experiments showed that birds rely on the sun to guide them during daylight hours. But what about birds that fly at night? Tests with artificial stars have proved that certain night -- flying birds are able to follow the stars in their long-distance flights.
A dove had spent its lifetime in a cage and had never flown under a natural sky. Yet it showed an inborn ability to use the stars for guidance. The bird’s cage was placed under an artificial star- filled sky. The bird tried to fly in the same direction as that taken by his outdoor cousins. Any change in the position of the artificial stars caused a change in the direction of his flight.
But the stars are apparently their principal means of navigation. When the stars are hidden by clouds, they apparently find their way by such landmarks as mountain ranges, coast lines, and river courses. But when it’s too dark to see these, the doves circle helplessly, unable to find their way.
The reasons why birds don’t get lost on long flights ______.
选项
A、have been known to scientists for years
B、have only recently been discovered
C、are known by everyone
D、will probably remain a mystery
答案
B
解析
本篇第一段说这个问题多年来使科学家迷惑不解,但随后又说:“Now they’re beginning to fill in the blanks.”这里“逐渐开始填补这些空白”意即“逐渐开始对所了解”。
转载请注明原文地址:https://kaotiyun.com/show/dwMK777K
本试题收录于:
大学英语三级B级题库大学英语三级分类
0
大学英语三级B级
大学英语三级
相关试题推荐
A、Yes,please.B、It’svery-kindofyou.C、That’sallright.D、Mypleasure.A对于这种问题的回答是同定的,肯定回答用Yes,please.否定回答用No,thanks,故选A。
DearMs.PamHill,AfriendinformedmethattheChicagoofficeofyourcompany,B.S.Accounting,isactivelyseekingtohire
Oneofthemostimportantgoalsofeducationisthe【11】ofacademicexcellence,notjustforafew【12】childrenbutforeveryo
Somecompaniesmightnotletyourentacar______youhaveacreditcard.
Bodylanguagereferstoexpressionsandbodymovements.Itisanimportantwayofcommunicationapartfrom【11】Asmileandhandsh
TheworstrecessionsinceWorldWarIItookplaceonthehighstreet,withoneintenstoresleftemptyaswoundedretailersgo
WhoisWilliamJackson?Heisthedirectorof______inHealthManagementService.Inc.Whataboutthenumberofthebeds
A、Nicetomeetyou.B、Whereisyourclassroom?C、That’sgreat.D、MybrotherisJack.A本题考查初次见面时的介绍用语和回答。题目意思为“让我来介绍一下自己,我是一年级七班的
I’msorrytohavespentsomuchmoney.Iwishyou______so.
Mr.Nathan,LadiesandGentlemen:TomorrowMr.Nathanwillconcludehisvisittoourcompanywithroundsuccess.Ourdinnert
随机试题
简述庾信入北前后诗风的变化。
关于卵巢肿瘤蒂扭转哪种说法是错误的:
下列有关行政强制执行的说法正确的有:
供配电系统短路电流计算中,在下列哪些情况下,可不考虑高压异步电动机对短路峰值电流的影响?()
背景:某开发公司的造价工程师在某公寓建设过程中,采用价值工程的方法对该工程的设计方案、施工方案进行了全面的技术经济评价,取得了良好的经济效益和社会效益。问题:1)表4为造价工程师针对设计院提出的三个设计方案,在征求各方专家意见后汇总而得到的功能
83,86,94,102,135,90,83,()。
撰写实验研究报告需要注意哪些方面?
依据《婚姻法》,有下列情形调解无效,应判决准予离婚的是()。
WelearnfromthepassagethatParagraphs2and3arewrittento
TheinventionofirrigationismeaningfulbecauseitcouldhelptoWhichoffollowingtendstowarmtheclimate?
最新回复
(
0
)