首页
登录
职称英语
Why don’t birds get lost on their long flights from one place to anothe
Why don’t birds get lost on their long flights from one place to anothe
游客
2024-07-12
12
管理
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. [br] 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
从文章第一段最后一句话“Now they’ re starting to fill 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://tihaiku.com/zcyy/3674176.html
相关试题推荐
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?S
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?S
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?S
Jacklosthisjobayearagoandhe______anotherjobyet.A、hasfoundB、hasn’tf
Jacklosthisjobayearagoandhe______anotherjobyet.A、hasfoundB、hasn’t
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?Sc
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?Sc
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?Sc
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?S
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?S
随机试题
WhilemotherwasinNewOrleans,Iwasinthecareofmygrandparents.They
Whatconcernwillthetest-tubebabyraiseaccordingtothepassage?[br]Which
商业银行工作人员利用职能便利,挪用本单位或客户资金的,按( )惩处。A.金融诈
突变型菌株经过再次突变又可成为与野生型相同表型的过程称为A:自发突变B:诱导突
针对某些社区矫正服务对象在求职过程中存在的自卑、人际沟通困难等问题,社会工作者设
肾阳虚之虚劳治疗当用( ) A.左归丸 B.右归丸 C.拯阳理劳汤 D
从我国取得财政收入的形式来看,国家发行的国库券收入属于哪种收入?()A.税收收
组合层面的风险监测把多种信贷资产作为投资组合进行整体监测。关于商业银行组合风险监
关于治理通货紧缩的货币主义政策主张的说法,错误的是()。A、以经济自由化
在某矿区内拟建设一座35/10kV变电所,两回35kV架空进线,设两台主变压器型
最新回复
(
0
)