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
2023-09-30
49
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/3057914.html
相关试题推荐
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?Scient
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?S
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?S
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?S
Jacklosthisjobayearagoandhe______anotherjobyet.A、hasfoundB、hasn’tf
Jacklosthisjobayearagoandhe______anotherjobyet.A、hasfoundB、hasn’t
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?Sc
Jacklosthisjobayearagoandhe______anotherjobyet.A、hasfoundB、hasn’tf
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?S
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?S
随机试题
Tousitseemssonaturaltoputupanumbrellatokeepthewateroffwheni
[originaltext]Thehomeisthecentralfocusofmostyoungpeople’slivesin
Itookaglimpseofthetaxibeforeitdisappearedaroundthecornerofthestre
Trafficfumesrenderthescentofflowersbarelyrecognizabletohoneybeesan
人的本质在其现实性上是一切社会关系的总和,这是因为()A.人的本质归根到底是由他
(2019年真题)证券登记结算公司依据《证券法》履行相关职能,说法正确的是()。
上层管理者不宜下放的职责有()。 A.参与质量委员会的工作B.批准质量方针
马克思主义产生的阶级基础和实践基础是( ) A.资本主义的剥削和压迫 B.
公民具有权利能力,并不必然具有行为能力。 ()
在高层建筑室内的塑料排水管道管径大于或等于110mm时,应设阻火圈的位置有(
最新回复
(
0
)