考研每日一练（2019/6/5）

第1题：设备控制器是可编址设备，当用于控制多台设备时，则具有多地址。

【判断题】： 对    错

第2题： 两周患病率的计算公式是 A．调查前两周内患病人(次)数/调查人数×100% B．调查前两周内患病人(次)数/需住院患者数×100% C．调查前两周内患病人(次)数/调查患者数×100% D．调查前两周内患病人(次)数/需就诊患者数×100% E．调查前两周内患病人(次)数/已住院患者数×100%

【单选题】： A     B     C     D     E

第3题：治疗气火上逆所致的妇女倒经，宜选用 A．鸡血藤 B．夏天无 C．郁金 D．红花 E．泽兰

【单选题】： A     B     C     D     E

第4题：已知A是3阶实对称矩阵，α1=(1，-1，-1)T，α2=(-2，1，0)T是齐次方程组Ax=0的解，又A-6E、α=0，α≠0． (Ⅰ)求α和二次型xTAx表达式． (Ⅱ)用正交变换X=Qy化二次型xTAx为标准形并写出所用坐标变换． (Ⅲ)求A-3E、6．

【分析题】：

第5题：关于腹主动脉瘤的叙述，哪项是错误的 A．动脉粥样硬化是引起腹主动脉瘤的最常见原因 B．多数患腹主动脉瘤的病人自觉无任何症状 C．腹主动脉瘤是动脉瘤中最常见的疾病 D．多数动脉瘤穿破入十二指肠或空肠并发上消化道出血

【单选题】： A     B     C     D

第6题：EI Nino is the term used for the period when sea surface temperatures are above normal off the SouthAmerican coast along the equatorial Pacific, sometimes called theEarth’s heartbeat, and is a dramatic but mysterious climate system that periodically rages across the PacifiC、 EI Nino means "the little boy" or "theChrist child" in Spanish, and is so called because its warm current is felt along coastal Peru andEcuador aroundChristmas.But the local warming is just part of an intricate set of changes in the ocean and atmosphere across the tropical Pacific, which covers a third of theEarth’s circumference. Its intensity is such that it affects temperatures, storm tracks and rainfall around the worlD、 Droughts inAfrica andAustralia, tropical storms in the Pacific, torrential rains along theCalifornian coast and lush greening of Peruvian deserts have all been ascribed to the whim ofEI Nino. Until recently it has been returning about every three to five years.But recently it has become more frequent--for the first time on record it has returned for a fourth consecutive year--and at the same time a giant pool of unusually warm water has settled clown in the middle of the Pacific and is showing no signs of moving. Climatologists don’t yet know why, though some are saying these aberrations may signal a worldwide change in climate. The problem is that nobody really seems sure what causes theEI Nino to start up, and what makes some stronger than others.And this makes it particularly hard to explain why it has suddenly started behaving so differently. In the absence ofEI Nino and its cold counterpart, La Nina, conditions in the tropical eastern Pacific are the opposite of those in the west: the east is cool and dry, while the west is hot and wet. In the east, it’s the winds and currents that keep things cool. It works like this. Strong, steady winds, called trade winds, blowing west across the Pacific drag the surface water along with them. The varying influence of theEarth’s rotation at different latitudes, known as theCoriolis effect, causes these surface winds and water to veer towards the poles, north in the northern hemisphere and south in the southern hemisphere. The surface water is replaced by colder water from deeper in the ocean in a process known as upwelling. The cold surface water in turn chills the air above it. This cold dense air cannot rise high enough for water vapor to condense into clouds. The dense air creates an area of high pressure so that the atmosphere over the equatorial eastern Pacific is essentially devoid of rainfall. The writer begins the text with A、a description of a scene. B．a root cause ofEI Nino. C．a narrative of an event. D．a definition ofEI Nino.

【单选题】： A     B     C     D

第7题：Is athletic expertise attained or innate Those who have suffered the tongue-lashing of a cruel games master at school might be forgiven for doubting the idea that anyone and everyone is capable of great sporting achievement, if only they would put enough effort into it. Practice may make perfect, but not all are built in ways that make it worth bothering in the first place. The latest evidence of this truth has been gathered by Sabrina Lee of Simon Fraser University in Vancouver and Stephen Piazza at Pennsylvania State University. They have looked at the physical structure of short-distance runners and found that their feet are built differently from those ofcouch potatoes. Dr. Lee andDr. Piazza already knew that short-distance runners tend to have a higher proportion of fast-contracting muscle fibres in their legs than more sedentary folk can muster. They suspected, though, that they would find differences in the bone structure as well.And they diD、 They looked at seven university sprinters who specialize in the 100-metre dash and five 200-metre specialists, and compared them with 12 non-athletic university students of the same height. In particular, they looked at the sizes of bones of the toes and heel. They also used ultrasonic scanning to measure the sliding motion of theAchilles tendons of their volunteers as their feet moved up and down. This allowed them to study the length of the lever created by the tendon as it pulls on the back of the heel to make the foot flex and push off the grounD、 Dr. Lee andDr. Piazza found that the toes of their short-distance runners averaged 8.2cm in length, while those of common people averaged 7.3cm. The length of the lever of bone that theAchilles tendon pulls on also differed, being a quarter shorter in short-distance runners. These findings suggest short-distance runners get better contact with the ground by having longer toes. That makes sense, as it creates a firmer platform to push against. In a short-distance running race, acceleration off the block is everything.Cheetahs, the champion of short-distance runners of the animal kingdom, have non-flexible claws that give a similar advantage. It is possible—just—that the differences in physical structure are the result of long and rigorous training.But it is unlikely. Far more probable is that the old saying of coaches, that great short-distance runners are born not made, is true.Everyone else, games masters included, should just get used to the ideA、 Which ofthe followings is NOT included in the latest evidence gathered byDr. Lee andDr. Piazza [A] The toes of their short-distance runners are longer than those of common people. [B] Short-distance runners tend to have a higher proportion of fast-contracting muscle fibres in their legs. [C] In short-distance runners, the length of the lever of bone that theAchilles tendon pulls on is considerably shorter. [D] The average length of toes of the tested common people is 7.3cm.

【单选题】： A     B     C     D

第8题：

【分析题】：

第9题：已知 在(-∞，+∞)上存在原函数，求常数A并求f(x)的原函数。

【分析题】：

第10题：Financial engineers don’’t wear white lab coats. They don’’t experiment on rats or perform gas chromatography(气相层析). Their raw material-money-isn’’t as showy as what biologists and physicists investigate.But the innovations they produce will contribute just as much to economic growth.　　Maybe more, in fact, because without the science of finance, all other sciences are just a bunch of neat concepts. Ideas begin to tribute to human betterment when they’’re financed-by venture capital, stock offerings, loans, or buyouts. A、smoothly operating financial system showers money on good ideas.Equally important, it cuts off funding to tired ideas and tired companies, so their assets can be employed more efficiently elsewhere.　　In the 21st century economy, innovation in finance will increase in concert with the increase in competition. Partly because of deregulation and globalization, competition should get tougher, and margins thinner.As products such as home mortgage loans become commoditized, financial- service companies will be forced to get more creative.　　Financial technology will keep feeding off information technology. The secret to success will be a strong software platform, which will lower the cost of general services while making it possible to create high-margin variations as well. A、few companies that get it right can spin away from the rest and become stronger and stronger.　　In the new world of finance, size counts.Big companies enjoy economies of scale and name recognition, and they can be safer because their bets are spread across more regions and market segments. The value of U. S. bank mergers in the first half of 1998 was greater than that of the three previous years combineD、The mergers are occurring across industries as well.　　At the other extreme will be specialists that survive by doing one thing either very cheaply or exceptionally well.By offering lower prices or better service, specialists will discipline the financial supermarkets; the big guys know their customers can walk away if they get a raw deal. "There is no way we are going to maximize a short-term transactional benefit at the risk of destroying a long-term relationship," saysChase ManhattanCorp. Vice-Chairman Joseph G. Sponholz.　　Predictably, the biggest winners from financial innovation will be companies, and families that have complex finances.Banks already show signs of losing interest in people who want just plain checking accounts.　　But as incomes and wealth rise, more people will find themselves thrust into the role of asset managers.Businesses, too, will have to become more sophisticated-if only to keep pace with financially innovative rivals.. In comparison with natural scientists, financial engineers A、may give even greater impetus to social development. B． can show more attention-getting features of their work. C．are more likely to make full use of their raw material. D． will produce as many innovations to advance economy.

【单选题】： A     B     C     D