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
2013-04-22
65
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 ascientific 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 them 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 thousand fold.
【C17】
选项
A、to
B、as
C、for
D、with
答案
D
解析
with短语表示具有、带有,其他介词短语不能表示这种意思。
转载请注明原文地址:https://kaotiyun.com/show/UEQK777K
0
专业英语四级
相关试题推荐
Signhasbecomeascientifichot【C1】______.【C2】______inthepast20yearshavespecialistsinlanguagestudyrealizedthatsigne
Seventy-four-year-oldsarethemost【C1】______peopleinthepopulation,accordingtoanewresearch.Fewerresponsibilities,fina
Seventy-four-year-oldsarethemost【C1】______peopleinthepopulation,accordingtoanewresearch.Fewerresponsibilities,fina
Didyousleepwelllastnight?Ordidyouwakeupfeelingfatiguedandsluggish—perhapsevenwonderingifyoureallysleptat
Whatdoyoulookforinapotentialdate?Sincerity?Goodlooks?Character?Conversationalability?Askedto【C1】______suchquali
Accordingtothepassage,mothersin______spendmoretimelookingafterchildren.
Incontrasttologic,thereiscommonsense,orstillbetter,theSpiritofReasonableness.IthinkoftheSpiritofReasonablen
Thursdaynight’sprogrammeonITV1,TheCostofGoingGreen,providedareasonablybalanceddebateontheimpactsofrenewablee
Openupmostfashionmagazinesandyouwillseeincrediblythinmodelswithimpossiblehairandwearingunreasonablyexpensive,
Togiveyouageneralideaofourproducts,weenclosethecataloguesshowingvariousproductshandledbyuswithdetailedandm
随机试题
论述美国独立战争后主要社会转型及对美国历史发展的影响。(四川大学2016年世界通史真题)
重型病毒性肝炎患者,出血倾向最主要的是()
腰痛多年,时轻时重,伴双下肢痛。10d前搬重物后腰腿痛加剧,并出现麻木与排尿困难。查体:腰运动受限,椎旁压痛向下肢放散,直腿高举与足背屈附加试验阳性。马鞍区痛觉减退。最主要的治疗措施是
根据我国宪法,有关国家机关可以在哪些情形下依照法定程序对公民的通信进行检查?
美国《科学》杂志指出,21世纪以来,全球平均气温一直在持续上升。其结论主要依据政府间气候变化专门委员会于2013年发布的一份报告以及对美国国家海洋与大气管理局运作的全球温度记录进行的修正记录(纠正已知的海洋表面温度记录的偏差,吸纳新的延伸到北极的陆基监测站
根据上图,2008年至2012年间,下列说法正确的是()。
李某与企业签订了为期5年的劳动合同,履行了3年后双方经协商解除了劳动合同。有关该事件的表述哪个是正确的?()
当N次实验中的干扰项成为N+1次实验的靶子时,被试对它的反应会变慢,这种现象是
Withunemploymenttidethroughouttherichworld,moreandmoreyoungpeopleareseekinginternships.Manyfirms,nervousabout
Pregnancymothersaregettinganewtooltohelpkeepthemselvesandtheirbabieshealthy:pregnancytipssentdirectlytotheir
最新回复
(
0
)