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 a long
Why don’t birds get lost on their long flights from one place to another? Scientists have puzzled over this question for a long
admin
2015-04-17
102
问题
Why don’t birds get lost on their long flights from one place to another? Scientists have puzzled over this question for a long time. Now they’ re starting to fill in the blanks.
Not long ago, experiments showed that birds use the sun to guide them during daylight hours. How do birds 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. But it had 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 main means of navigation. When the stars are hidden by clouds, they apparently find their way by such landmarks as river courses, mountain ranges, coast lines. But when it’ s too dark to see these things, the doves circle helplessly, unable to find their way.
The reasons why birds don’t get lost on their 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
题干意为“在长途飞行过程中鸟儿不会迷路的原因______。”从文章第一段最后一句话“Now they’re starting to fin in the blanks.”可以得出答案B。A项“科学家们已经掌握多年了”;C项“每个人都知道”;D项“将有可能继续是一个谜”,都不符合文意。
转载请注明原文地址:https://kaotiyun.com/show/4W0K777K
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、It’sOctober1,2002.B、It’scloudytoday.C、It’sinChina.D、It’shalfpastsix.B
Atallevents,donotmakeanymentionofittoothers.
Thispartistotestyourabilitytodopracticalwriting.Youarerequiredtowritealetterofapplicationaccordingtothefo
A、About20hours.B、Solong.C、Veryfast.D、Iusuallygohomebyair.A“Howlong…?”是询问多长时间的疑问词,本题问的是“你坐火车回家要多长时间?”B、C、D三项都不符合题意,
Personswhoareoverweightshouldwatchtheirdietcarefullyinordertolosepounds.Thebestwaytodothisistostartaweig
On5thOctober,Iboughtoneofyourexpensive"Apollo"fountainpensfromJulian’s(朱利安公司),abigdepartmentstoreofthistown.
A、Thankyou.B、Icanmanageitbymyself.C、I’msufferingfromacold.D、It’sverykindofyou.C本题问及健康状况,“你今天有点不对劲,是不是哪里不舒服?”
Duringworkinghours,thetrafficisveryheavyonmostcitystreets;thereforeyoushouldbeawareofthetrafficlaws.Itisa
欢迎新同事说明:假定你是经理TimHuston,代表公司写一份欢迎信给新来的同事JessicaSmith.内容:1.对JessicaSmith表示欢迎;JessicaSmith是个优秀的设计师,公司很幸运有她的加入;
The(long)______oftheriveris3,000miles.
随机试题
袋中有6个球,分别标有数字1,2,3,4,5,6,从中一次任取两个球,试求:取出的两个球上的数字之和大于8的概率.
左旋多巴对吩噻嗪类药物引起的帕金森综合征无效。
检查泌尿系结石首选
中毒表现为惊厥、痉挛,甚至角弓反张,是因中毒表现为胸闷、心悸、心律不齐,心电图显示房室传导阻滞,是因
为了保护债务人的利益不受侵害,受让人对于让与人基于同一债权而应该承担的义务也应承受,包括( )。
下列属于湖北省主要名菜的有()。
当代中国的基本国情是()。
2006年人才蓝皮书指出,在中国、美国、日本、德国、俄罗斯和印度六国人才国际竞争力排名中,中国位居第四位,仅排在俄罗斯和印度之前,属于第三层次。中国人才国际竞争力远低于排在第一位的美国,仅相当于美国的48%,总体差距非常明显。 不过,令人意外的是,我国
2006年12月召开的中央农村工作会议强调,建设现代农业、推进新农村建设的根本保证是
列宁针对殖民地半殖民地国家的状况,指出:“认为无产阶级政党(如果它一般地说能够在这类国家里产生的话)不同农民运动发生一定的关系,不在实际上支持农民运动,就能在这些落后国家里实行共产主义的策略和共产主义的政策,那就是空想”毛泽东认为:农民是“中国工人的前身”
最新回复
(
0
)