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
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 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
Whetheryou’retheCEOofaFortune500company,orateenageentrepreneurjuststartingout,communicationskillsarevitally
Earlyanthropologists,followingthetheorythatwordsdeterminethought,believedthatlanguageanditsstructurewereentirel
Forcountlesstimesinhistory,peoplehaveexploredtherelationshipbetweenscienceandclassics.Thepioneersoftheteachin
Thelandofapplepieandbaseball—theUnitedStatesofAmerica.OfcourseweallknowthereismoretoAmericathanapplepie
IntheearlydaysoftheUnitedStates,postalchargeswerepaidbytherecipients,andchargesvariedwiththedistancecarried
WashingtonfeltuncomfortableinCongressdebatesbecausehe_______.
Ingeneral,therearefourkindsofconflict:conflictbetweenpeople,conflictwithoneself,conflictwithnature,andconflic
ScientistsareinterestedinMarsbecause_______________.
WhenamajorpoweroutageleftevenTimesSquareeerilydark,NewYorkCity’sfaithfulheadedoutoftheirhotapartmentsandst
There’samanatthereceptiondeskwhoseemsveryangryandIthinkhemeans______trouble.
随机试题
根据脂肪含量,成熟型卵巢畸胎瘤CT可表现类型,除外
查体最可能的发现的是治疗原则
郁证实证治疗以何为主
《红楼梦》中的林黛玉,其动作稳定缓慢,观察事物细致入微,敏感多疑,孤独多虑,情感体验深刻而持久。她的气质类型属于
患儿,9岁。右上1区冠折1/3,露出粉红针尖佯网点,叩(+),不松,穿髓孔直径不超过0.5mm,牙龈无明显异常,X线片示:未见根折,根尖呈喇叭口状.治疗宜选择
财务报表应当以()为截止日。
(1)给南京莫愁湖郁金堂联断句、标点。湖属卢家唯江头明月曾领略画艇风光韵事相传与骚人作诗料地归徐氏以国手胜棋博优游名园汤沐英雄安在遥闻商女唱歌声(2)解释词语。①骚人②优游③商女
资本的自然属性是逐利性,但资本也______承担相应的社会功能。当资本的逐利性与其社会功能不能______共存时,这就要求政府充当社会属性的执行者和监管者,因为政府是公共利益的代表者。填入划横线部分最恰当的一项是()。
2011年全国农民工总量达到25278万人,比上年增加1055万人。其中,外出农民工15863万人,增加528万人,增长3.4%。住户中外出农民工12584万人,比上年增加320万人;举家外出农民工3279万人,增加208万人。本地农民工9415万人,增加
在Access中已建立了"学生"表,其中有可以存放简历的字段,在使用向导为该表创建窗体时,"简历"字段所使用的默认控件是()。
最新回复
(
0
)