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
57
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.
【C20】
选项
A、perception
B、experience
C、reception
D、experiment
答案
A
解析
B:经验、体验;C:接待、接纳;D:实验、试验。只有A“感觉、感知”符合句意。
转载请注明原文地址:https://kaotiyun.com/show/LEQK777K
0
专业英语四级
相关试题推荐
Seventy-four-year-oldsarethemost【C1】______peopleinthepopulation,accordingtoanewresearch.Fewerresponsibilities,fina
Seventy-four-year-oldsarethemost【C1】______peopleinthepopulation,accordingtoanewresearch.Fewerresponsibilities,fina
Seventy-four-year-oldsarethemost【C1】______peopleinthepopulation,accordingtoanewresearch.Fewerresponsibilities,fina
Onceuponatime,youbelievedinthetoothfairy.Youcountedonthestabilityofhousingpricesanddependedonbankerstobe,
Whatdoyoulookforinapotentialdate?Sincerity?Goodlooks?Character?Conversationalability?Askedto【C1】______suchquali
Accordingtothepassage,mothersin______spendmoretimelookingafterchildren.
Welearnfromthepassagethatabouttwo-thirdsofthecoursesaretaughtthrough______.
Decidewhichofthechoicesgivenbelowwouldbestcompletethepassageifinsertedinthecorrespondingblanks.Mostworthw
Thereason______hisgoingtoFrancewas______hegotanewjobthere.
WhichofthefollowingrelationshipisNOTmentionedinthispassage?
随机试题
下列选项中,属于诉讼时效中断的法定事由有()。
试述中国家庭结构的文化要素。
目前,对基金信息披露进行管理的部门主要有()。
甲省地区因连续降雨,导致甲省A市康康药厂生产废物未及时运输到指定的废物清理点,生产废物被雨水浸泡且蔓延到居民居住地附近的路面,造成环境污染。经群众举报,A市环境保护局了解情况后,立即向康康药厂送达决定书,责令其立即清扫废物并合理处理,恢复路面原状,并处以罚
某企业生产过程的机械化、自动化水平比较高,工人操作技术单一,熟练程度高,说明该企业的生产类型属于()。
在对某起生产事故原因的调查中,70%的人认为是设备故障;30%的人认为是违章操作;25%的人认为原因不清,需要深入调查。以下哪项最能合理地解释上述看来包含矛盾的陈述?()
营业外收入是指与企业生产经营活动没有直接关系的各种收入。作为营业外收入,必须同时具备两个特征:一是意外发生,企业无力加以控制;二是偶然发生,不重复出现。根据上述定义,下列不属于营业外收入的是:
以下合法的变量名是
关于结构化程序设计原则和方法的描述错误的是()。
Themeeting(last)______afullweekbythetimeitends.
最新回复
(
0
)