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
The ability of falling cats to right themselves in midair and land on their feet has been a source of wonder for ages. Biologist
The ability of falling cats to right themselves in midair and land on their feet has been a source of wonder for ages. Biologist
admin
2010-02-17
38
问题
The ability of falling cats to right themselves in midair and land on their feet has been a source of wonder for ages. Biologists long regarded it as an example of 【C1】______ by natural selection, but for physicists it bordered on the miraculous. Newton’s laws of motion 【C2】______ that the total amount of spin of a body cannot change 【C3】______ an external torque speeds it up or slows it down. If a cat has no spin when it is released and experiences no external torque, it ought not to be able to 【C4】______ as it falls.
In the speed of its execution, the 【C5】______ of a tumbling cat resembles a magician’s trick. The gyrations of the cat in midair are 【C6】______ fast for the human eye to follow, so the process is obscured.【C7】______ the eye must be speeded up, or the cat’s fall slowed down for the phenomenon to be observed. A century ago the former was accomplished 【C8】______ high-speed photography using equipment now 【C9】______ in any pharmacy. But in the nineteenth century the 【C10】______ on film of a falling cat constituted a scientific experiment.
The experiment was described in a paper presented to the Paris Academy in 1894. Two sequences of twenty photographs【C11】______ one from the side and one from behind, 【C12】______ a white cat in the act of righting itself. Grainy and quaint 【C13】______ they are, the photos show that the cat was dropped upside down, with no initial spin, and still landed on its feet. Careful analysis of the photos reveals the secret. As the Cat rotates the front of its body 【C14】______ , the rear and tail twist counterclockwise, 【C15】______ the total spin remains zero, 【C16】______ Newton’s laws. Halfway down, the cat pulls in its legs before reversing its twist and then extends them again, 【C17】______ the desired end result. The explanation was that while no body can acquire spin without torque, a flexible one can readily change its 【C18】______ . Cats know this instinctively, but scientists could not be sure how it happened 【C19】______ they increased the speed of their 【C20】______ a thousandfold.
【C13】
选项
A、though
B、as
C、than
D、and
答案
B
解析
though不用于倒装句,又要表示让步,又要倒装,要选B。C和D显然不对。
转载请注明原文地址:https://kaotiyun.com/show/aOnK777K
0
专业英语四级
相关试题推荐
Thereareseveralpossiblerelationshipsbetweenlanguageandsociety.Oneisthatsocialstructuremayeitherinfluenceordet
Whichofthefollowingregionsintheworldwillwitnessthesharpestdropinlifeexpectancy?
Somepessimisticexpertsfeelthattheautomobileisboundtofallintodisuse,Theyseeadayinthenot.too-distantfuturewh
WashingtonfeltuncomfortableinCongressdebatesbecausehe_______.
Geographyisthestudyoftherelationshipbetweenpeopleandtheland.Geographerscompareandcontrast【C1】______ placesonthe
Unlikemostsports,whichevolvedovertimefromstreetgames,basketballwasdesignedbyonemantosuita【C1】______purpose.
Aprobabletitletothispassagemightbe______.
Thespeakeristalkingtoa______.
Yesterday’sstrikecausedthemostconfusionfor______.
SomecallittheSmartShooter,anewrifleforAmericaninfantrytroopsthatistwoweaponsinone,isaccurateupto1,000yar
随机试题
_______________出现以前的横断层面上无尾状叶,_______________出现以后的横断层面上固有尾状叶消失;第二肝门至胆囊窝之间的横断层面上,尾状叶借_______________裂与_______________叶、__________
资金流量表按机构部门顺序排列,其包括的部门有()
根据《民事诉讼法》的规定,下列关于审判制度的表述中,不正确的是()。
下列各项内容构成融资租赁中最低租赁付款额的组成部分的是()。
阅读下列材料,完成小题。材料一“厄尔尼诺”是指在赤道太平洋东部的大面积海域,出现呈2—7年周期性的海水温度异常增高的现象。“厄尔尼诺”影响范围广、危害大,在全世界范围内造成巨大的经济损失。材料二下图是“厄尔尼诺”年份海水温度距平等值线图(单位℃)。
皮肤破损出血、颈髓损伤、锐器插人体内、严重挤压伤等是灾害发生时的常见损伤类型,掌握科学的自救方法对于延续生命、等待救援很重要。下列自救措施中,恰当的是()。
生命意义的问题不可能还原为经验研究。如果所有认识论上的问题都可以由科学探究在实践中得到解决,那么,我们可能会觉得,即使所有这些问题在一觉醒来都得到了解决,这仍然与生命的意义这一问题毫无瓜葛,与美好的人类生活究竟包含着什么这个问题无关。这段文字所表达的主要意
什么是“导向需求”?宅与“议程设置”效果有什么关联?
关于数据库应用系统的需求分析工作,下列说法正确的是()。
Agloomyafternoonsawmetakingmyroutinepaththroughthatconstructionsite.Forthewalker’sconvenience,asetofstones
最新回复
(
0
)