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
49
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
WhichofthefollowingstatementsisINCORRECT?Accordingtothepassage,theNazcalineswerefound______.
Incontrasttologic,thereiscommonsense,orstillbetter,theSpiritofReasonableness.IthinkoftheSpiritofReasonablen
Accordingtothepassage,theaverageageofthefleetofDelta/Northwestis______.
WhichofthefollowingisNOTthereasonthatthemanwantstogoonadiet?
Accordingtothepassage,FrenchwomenarenotmentionedleadingEuropeas______.
WhichofthefollowingrelationshipisNOTmentionedinthispassage?
Whichisnotmentionedinthepassageasanaspectthatfarmingactivitiesaredamaging?
随机试题
计算下列不定积分:
当x→0+时,下列变量与x为等价无穷小量的是()
结直肠癌的主要转移途径为()
82,63,50,()
我国之所以提出构建社会主义和谐社会,就是因为我国的经济发展,超前于我国的政治、文化及社会的发展,因此,当前我国一切工作的中心已经不是经济建设。()
阅读《水龙吟.登建康赏心亭》教学实录片段,回答问题。案例:师:我们现在做个小练习,大家将以下词人按照婉约派和豪放派进行划分。(PPT展示:柳永苏轼李清照秦观温庭筠辛弃疾岳飞)(生讨论发言,教师
我国实行适度宽松的货币政策,降低存款利率不利于()。
企业文化是指一个企业中所有员工共有的一套观念、信念、价值和行为准则,以及由此导致的行为模式。根据此定义,以下理解或说法正确的是()。
一种错误的认识是,只有热情开朗乃至经常喋喋不休的人,才有更强的适应性,也更容易在群体中受欢迎。这种印象让那些内向的人有些自卑,甚至怀疑自己有社交障碍。转而求助于心理医生或抗抑郁药物。但大可不必如此,因为________。有研究显示,大约有30%的人生性内向
有三个关系R、S和T如下: 则由关系R和关系s得到关系T的操作是()。
最新回复
(
0
)