2013年考研真题及答案
2013年考研数二真题及详细解析
2013年全国硕士研究生入学统一考试数学二试题一、选择题：1～8小题，每小题4分，共32分，下列每小题给出的四个选项中，只有一项符合题目要求的，请将所选项前的字母填在答题纸．．．指定位置上. （1）设cos 1sin ()x x x α-=，其中()2x πα<，则当0x →时，()x α是（ ）（A ）比x 高阶的无穷小 （B ）比x 低阶的无穷小 （C ）与x 同阶但不等价的无穷小 （D ）与x 等价的无穷小（2）设函数()y f x =由方程cos()ln 1xy y x +-=确定，则2lim ()1n n f n→∞⎡⎤-=⎢⎥⎣⎦（ ）（A ）2 （B ）1 （C ）1- （D ）2- （3）设函数sin ,0()=2,2x x f x x πππ≤<⎧⎨≤≤⎩，0()()x F x f t dt =⎰，则（ ）（A ）x π= 是函数()F x 的跳跃间断点 （B ）x π= 是函数()F x 的可去间断点（C ）()F x 在x π=处连续但不可导 （D ）()F x 在x π=处可导（4）设函数111,1(1)()=1,ln x e x f x x e x xαα-+⎧<<⎪-⎪⎨⎪≥⎪⎩，若反常积分1()f x dx +∞⎰收敛，则（ ）（A ）2α<- （B ）2α> （C ）20α-<< （D ）02α<< （5）设()yz f xy x=，其中函数f 可微，则x z z y x y ∂∂+=∂∂（ ） （A ）2()yf xy ' （B ）2()yf xy '- （C ）2()f xy x （D ）2()f xy x- （6）设k D 是圆域{}22(,)|1D x y x y =+≤在第k 象限的部分，记()(1,2,3,4)kk D I y x dxdy k =-=⎰⎰，则（ ）（A ）10I > （B ）20I > （C ）30I > （D ）40I > （7）设矩阵A,B,C 均为n 阶矩阵，若,B AB C =则可逆，则 （A ）矩阵C 的行向量组与矩阵A 的行向量组等价 （B ）矩阵C 的列向量组与矩阵A 的列向量组等价 （C ）矩阵C 的行向量组与矩阵B 的行向量组等价 （D ）矩阵C 的行向量组与矩阵B 的列向量组等价2（8）矩阵1111a a b a a ⎛⎫ ⎪ ⎪ ⎪⎝⎭与2000b 0000⎛⎫ ⎪⎪ ⎪⎝⎭相似的充分必要条件为（A ）a 0,b 2== （B ）为任意常数b a ,0= （C ）0,2==b a（D ）为任意常数b a ,2=二、填空题：9-14小题，每小题4分，共24分，请将答案写在答题纸．．．指定位置上. (9) 1ln(1)lim(2)x x x x→∞+-= ． (10) 设函数()xf x -=⎰，则()y f x =的反函数1()x f y -=在0y =处的导数y dx dy== ．(11)设封闭曲线L 的极坐标方程为cos3()66r ππθθ=-≤≤，则L 所围成的平面图形的面积为 ．(12)曲线arctan ln x ty =⎧⎪⎨=⎪⎩1t =的点处的法线方程为 ．(13)已知321x x y e xe =-，22x x y e xe =-，23xy xe =-是某二阶常系数非齐次线性微分方程的3个解，该方程满足条件00x y==01x y ='=的解为y = ．（14）设ij A (a )=是三阶非零矩阵，|A |为A 的行列式，ij A 为ij a 的代数余子式，若ij ij a A 0(i,j 1,2,3),____A +===则三、解答题：15—23小题，共94分.请将解答写在答题纸．．．指定位置上.解答应写出文字说明、证明过程或演算步骤.（15）（本题满分10分）当0x →时，1cos cos2cos3x x x -⋅⋅与nax 为等价无穷小，求n 与a 的值。
2013年考研政治真题及答案
2013年考研政治真题及答案一、单选题：1.如果一项决策违背国家行为规范，它应该服从A) 社会行为习惯B) 行政行为规范C) 国家行政规范D) 国家行为规范答案：D解析：国家行为规范是最高的行为准则，其他选项不能代替。
2.下列哪种方式不属于公共行政常见的自我约束方式？A) 行为规范B) 真实记录C) 日志记录D) 自愿约束答案：A解析：公共行政的自我约束方式包括真实记录、日志记录和自愿约束，行为规范是一种行为准则，不属于自我约束方式。
3.社会保障的主要保障对象是A) 劳动者B) 企业C) 政府D) 公司答案：A解析：社会保障的主要保障对象是劳动者，旨在保护劳动者的权益。
4.我国资源环境承载力分析的阶段分为A) 警戒阶段、临界阶段和容许阶段B) 容许阶段、濒临饱和阶段和警戒阶段C) 容许阶段、濒临饱和阶段和超载阶段D) 警戒阶段、濒临饱和阶段和超载阶段答案：C解析：我国资源环境承载力分析的阶段分为容许阶段、濒临饱和阶段和超载阶段，这三个阶段体现了资源环境的可持续发展状况。
5.我国推行现代化经济体制改革的标志是A) 建设社会主义市场经济体制B) 实行市场化改革C) 发展私有制经济D) 推行计划经济体制答案：A解析：我国推行现代化经济体制改革的标志是建设社会主义市场经济体制，市场化改革和发展私有制经济是建设社会主义市场经济体制的重要内容。
二、判断题：1.社会主义国家的行政机构是资产阶级专政的工具。
答案：错误解析：社会主义国家的行政机构是无产阶级专政的工具，而不是资产阶级专政的工具。
2.在行政管理中，奖励和处罚是实现行政目标的手段。
答案：正确解析：奖励和处罚是行政管理中常用的手段，可以有效地激励和约束行政主体的行为，从而实现行政目标。
3.我国现行的政府预算制度是“中央授权、地方负责、审计监督”的分权制度。
答案：错误解析：我国现行的政府预算制度是“中央授权、地方执行、人大监督”的集权制度。
4.我国批评与自我批评是党内政治生活的重要方式之一。
2013考研数学一真题答案
2013年全国硕士研究生入学统一考试数学一试题答案一、选择题：1～8小题，每小题4分，共32分，下列每小题给出的四个选项中，只有一项符合题目要求的，请将所选项前的字母填在答题纸．．．指定位置上. （1）已知极限0arctan lim kx x xc x →-=，其中,c k 为常数，且0c ≠，则（ ）（A ）12,2k c ==-（B ）12,2k c ==（C ）13,3k c ==-（D ）13,3k c ==【答案】D【解析】33300011(())arctan 133lim lim lim ,3,3k k k x x x x x x o x xx x c k c x x x →→→--+-===∴== （2）曲面2cos()0x xy yz x +++=在点(0,1,1)-处的切平面方程为（ ） （A ）2x y z -+=- （B ）2x y z ++= （C ）23x y z -+=- （D ）0x y z --= 【答案】A【解析】设2(,,)cos()F x y z x xy yz x =+++， 则(,,)2sin()1(0,1,1)1x x F x y z x y xy F =-+⇒-=；(,,)sin()(0,1,1)1y y F x y z x xy z F =-+⇒-=-；(,,)(0,1,1)1z z F x y z y F =⇒-=，所以该曲面在点(0,1,1)-处的切平面方程为(1)(1)0x y z --++=， 化简得2x y z -+=-，选A20132（3）设()1(),[0,1]2f x x x =-∈，102()sin (1,2,...)n b f x n xdx n π==⎰，令1()sin n n S x b n x π∞==∑，则9()4S -=（ ）（A ）34（B ）14（C ）14-（D ）34-【答案】C【解析】根据题意，将函数在[1,1]-上奇延拓1,012()1,102x x f x x x ⎧-<<⎪⎪=⎨⎪----<<⎪⎩，它的傅里叶级数为()S x 它是以2为周期的，则当(1,1)x ∈-且()f x 在x 处连续时，()()S x f x =，因此991111()(2)()()()444444S S S S f -=-+=-=-=-=- （4）设222222221234:1,:2,:22,:22,l x y l x y l x y l x y +=+=+=+=为四条逆时针的平面曲线，记33()(2)(1,2,3,4)63ii l y x I y dx x dy i =++-=⎰，则()i MAX I =( )（A ）1I （B ）2I （C ）3I（D ）4I 【答案】D【解析】33()(2)(1,2,3,4)63i i l y x I y dx x dy i =++-=⎰22(1)2iDy x dxdy =--⎰⎰利用二重积分的几何意义，比较积分区域以及函数的正负，在区域14,D D 上函数为正值，则区域大，积分大，所以41I I >，在4D 之外函数值为负，因此4243,I I I I >>，故选D 。
2013年考研英语(一)真题及答案
2013年全国硕士研究生招生考试英语一试题Section I Use of EnglishDirections:Read the following text.Choose the best word(s)for each numbered blank and mark A,B,C or D on the ANSWER SHEET.(10points)①People are,on the whole,poor at considering background information when making individual decisions.②Atfirst glance this might seem like a strength that1the ability to make judgments which are unbiased by2factors.③But Dr Uri Simonsohn speculated that an inability to consider the big3was leading decision-makers to be biased by the daily samples of information they were working with.4,he theorised that a judge5of appearing too soft6crime might be more likely to send someone to prison7he had already sentencedfive or six other defendants only to forced community service on that day.①To8this idea,he turned to the university-admissions process.②In theory,the9of an applicant should not depend on the few others10randomly for interview during the same day,but Dr Simonsohn suspected the truth was11.①He studied the results of9,323MBA interviews12by31admissions officers.②The interviewers had13applicants on a scale of one tofive.③This scale14numerous factors into consideration.④The scores were15used in conjunction with an applicant’s score on the Graduate Management Admission Test,or GMAT,a standardised exam which is16out of800 points,to make a decision on whether to accept him or her.①Dr Simonsohn found if the score of the previous candidate in a daily series of interviewees was0.75points or more higher than that of the one17that,then the score for the next applicant would18by an average of0.075points.②This might sound small,but to19the effects of such a decrease a candidate would need30more GMAT points than would otherwise have been 20.1.[A]grants[B]submits[C]transmits[D]delivers2.[A]minor[B]external[C]crucial[D]objective3.[A]issue[B]vision[C]picture[D]moment4.[A]Above all[B]On average[C]In principle[D]For example5.[A]fond[B]fearful[C]capable[D]thoughtless6.[A]in[B]for[C]to[D]on7.[A]if[B]until[C]though[D]unless8.[A]test[B]emphasize[C]share[D]promote9.[A]decision[B]quality[C]status[D]success10.[A]found[B]studied[C]chosen[D]identified11.[A]otherwise[B]defensible[C]replaceable[D]exceptional12.[A]inspired[B]expressed[C]conducted[D]secured13.[A]assigned[B]rated[C]matched[D]arranged14.[A]put[B]got[C]took[D]gave15.[A]instead[B]then[C]ever[D]rather16.[A]selected[B]passed[C]marked[D]introduced17.[A]below[B]after[C]above[D]before18.[A]jump[B]float[C]fluctuate[D]drop19.[A]achieve[B]undo[C]maintain[D]disregard20.[A]necessary[B]possible[C]promising[D]helpfulSection II Reading ComprehensionPart ADirections:Read the following four texts.Answer the questions below each text by choosing A,B,C or D.Mark your answers on the ANSWER SHEET.(40points)Text1①In the2006film version of The Devil Wears Prada,Miranda Priestly,played by Meryl Streep,scolds her unattractive assistant for imagining that high fashion doesn’t affect her.②Priestly explains how the deep blue color of the assistant’s sweater descended over the years from fashion shows to department stores and to the bargain bin in which the poor girl doubtless found her garment.①This top-down conception of the fashion business couldn’t be more out of date or at odds with the feverish world described in Overdressed,Elizabeth Cline’s three-year indictment of“fast fashion”.②In the last decade or so,advances in technology have allowed mass-market labels such as Zara,H&M,and Uniqlo to react to trends more quickly and anticipate demand more precisely.③Quicker turnarounds mean less wasted inventory,more frequent releases,and more profit.④These labels encourage style-conscious consumers to see clothes as disposable—meant to last only a wash or two,although they don’t advertise that—and to renew their wardrobe every few weeks.⑤By offering on-trend items at dirt-cheap prices,Cline argues,these brands have hijacked fashion cycles,shaking an industry long accustomed to a seasonal pace.①The victims of this revolution,of course,are not limited to designers.②For H&M to offer a$5.95knit miniskirt in all its2,300-plus stores around the world,it must rely on low-wage overseas labor,order in volumes that strain natural resources,and use massive amounts of harmful chemicals.①Overdressed is the fashion world’s answer to consumer-activist bestsellers like Michael Pollan’s The Omnivore’s Dilemma.②“Mass-produced clothing,like fast food,fills a hunger and need,yet is non-durable and wasteful,”Cline argues.③Americans,shefinds,buy roughly 20billion garments a year—about64items per person—and no matter how much they give away, this excess leads to waste.①Towards the end of Overdressed,Cline introduced her ideal,a Brooklyn woman named Sarah Kate Beaumont,who since2008has made all of her own clothes—and beautifully.②But as Cline is thefirst to note,it took Beaumont decades to perfect her craft;her example can’t be knocked off.①Though several fast-fashion companies have made efforts to curb their impact on labor and the environment—including H&M,with its green Conscious Collection line—Cline believes lasting change can only be effected by the customer.②She exhibits the idealism common to many advocates of sustainability,be it in food or in energy.③Vanity is a constant;people will only start shopping more sustainably when they can’t afford not to.21.Priestly criticizes her assistant for her[A]lack of imagination.[B]poor bargaining skill.[C]obsession with high fashion.[D]insensitivity to fashion.22.According to Cline,mass-market labels urge consumers to[A]combat unnecessarywaste.[B]shop for their garments more frequently.[C]resist the influence of advertisements.[D]shut out the feverish fashion world.23.The word“indictment”(Para.2)is closest in meaning to[A]accusation.[B]enthusiasm.[C]indifference.[D]tolerance.24.Which of the following can be inferred from the last paragraph?[A]Vanity has more often been found in idealists.[B]The fast-fashion industry ignores sustainability.[C]Pricing is vital to environment-friendly purchasing.[D]People are more interested in unaffordable garments.25.What is the subject of the text?[A]Satire on an extravagant lifestyle.[B]Challenge to a high-fashion myth.[C]Criticism of the fast-fashion industry.[D]Exposure of a mass-market secret.Text2①An old saying has it that half of all advertising budgets are wasted—the trouble is,no one knows which half.②In the internet age,at least in theory,this fraction can be much reduced.③By watching what people search for,click on and say online,companies can aim“behavioural”ads at those most likely to buy.①In the past couple of weeks a quarrel has illustrated the value to advertisers of suchfine-grained information:Should advertisers assume that people are happy to be tracked and sent behavioural ads?Or should they have explicit permission?①In December2010America’s Federal Trade Commission(FTC)proposed adding a“do not track”(DNT)option to internet browsers,so that users could tell advertisers that they did not want to be followed.②Microsoft’s Internet Explorer and Apple’s Safari both offer DNT; Google’s Chrome is due to do so this year.③In February the FTC and Digital Advertising Alliance(DAA)agreed that the industry would get cracking on responding to DNT requests.①On May31st Microsoft set offthe row.②It said that Internet Explorer10,the version due to appear with Windows8,would have DNT as a default.①Advertisers are horrified.②Human nature being what it is,most people stick with default settings.③Few switch DNT on now,but if tracking is offit will stay off.④Bob Liodice,the chief executive of the Association of National Advertisers,says consumers will be worse offif the industry cannot collect information about their preferences.⑤People will not get fewer ads,he says.⑥“They’ll get less meaningful,less targeted ads.”①It is not yet clear how advertisers will respond.②Getting a DNT signal does not oblige anyone to stop tracking,although some companies have promised to do so.③Unable to tell whether someone really objects to behavioural ads or whether they are sticking with Microsoft’s default,some may ignore a DNT signal and press on anyway.①Also unclear is why Microsoft has gone it alone.②After all,it has an ad business too, which it says will comply with DNT requests,though it is still working out how.③If it is trying to upset Google,which relies almost wholly on advertising,it has chosen an indirect method:There is no guarantee that DNT by default will become the norm.④DNT does not seem an obviously huge selling point for Windows8—though the firm has compared some of its other products favorably with Google’s on that count before.⑤Brendon Lynch,Microsoft’s chief privacy officer,blogged:“We believe consumers should have more control.”⑥Could it really be that simple?26.It is suggested in Paragraph1that“behavioural”ads help advertisers to[A]lower their operationalcosts.[B]ease competition among themselves.[C]avoid complaints from consumers.[D]provide better online services.27.“The industry”(Para.3)refers to[A]online advertisers.[B]e-commerce conductors.[C]digital information analysts.[D]internet browser developers.28.Bob Liodice holds that setting DNT as a default[A]goes against human nature.[B]fails to affect the ad industry.[C]will not benefitconsumers.[D]may cut the number of junk ads.29.Which of the following is true according to Paragraph6?[A]Advertisers are willing to implement DNT.[B]DNT may not serve its intended purpose.[C]DNT is losing its popularity among consumers.[D]Advertisers are obliged to offer behavioural ads.30.The author’s attitude towards what Brendon Lynch said in his blog is one of[A]appreciation.[B]understanding.[C]indulgence.[D]skepticism.Text3①Up until a few decades ago,our visions of the future were largely—though by no means uniformly—glowingly positive.②Science and technology would cure all the ills of humanity, leading to lives of fulfillment and opportunity for all.①Now utopia has grown unfashionable,as we have gained a deeper appreciation of the range of threats facing us,from asteroid strike to epidemicflu and to climate change.②You might even be tempted to assume that humanity has little future to look forward to.①But such gloominess is misplaced.②The fossil record shows that many species have endured for millions of years—so why shouldn’t we?③Take a broader look at our species’place in the universe,and it becomes clear that we have an excellent chance of surviving for tens,if not hundreds,of thousands of years.④Look up Homo sapiens in the“Red List”of threatened species of the International Union for the Conservation of Nature(IUCN)and you will read:“Listed as Least Concern as the species is very widely distributed,adaptable,currently increasing,and there are no major threats resulting in an overall population decline.”①So what does our deep future hold?②A growing number of researchers and organisations are now thinking seriously about that question.③For example,the Long Now Foundation has as itsflagship project a mechanical clock that is designed to still be marking time thousands of years hence.①Perhaps willfully,it may be easier to think about such lengthy timescales than aboutthe more immediate future.②The potential evolution of today’s technology,and its social consequences,is dazzlingly complicated,and it’s perhaps best left to sciencefiction writers and futurologists to explore the many possibilities we can envisage.③That’s one reason why we have launched Arc,a new publication dedicated to the near future.①But take a longer view and there is a surprising amount that we can say with considerable assurance.②As so often,the past holds the key to the future:we have now identified enough of the long-term patterns shaping the history of the planet,and our species,to make evidence-based forecasts about the situations in which our descendants willfind themselves.①This long perspective makes the pessimistic view of our prospects seem more likely to bea passing fad.②To be sure,the future is not all rosy.③But we are now knowledgeable enough to reduce many of the risks that threatened the existence of earlier humans,and to improve the lot of those to come.31.Our vision of the future used to be inspired by[A]our desire for lives of fulfillment.[B]our faith in science and technology.[C]our awareness of potential risks.[D]our belief in equal opportunity.32.The IUCN’s“Red List”suggests that human beings are[A]a misplaced race.[B]a sustained species.[C]the world’s dominant power.[D]a threat to the environment.33.Which of the following is true according to Paragraph5?[A]The interest in sciencefiction is on the rise.[B]Arc helps limit the scope of futurological studies.[C]Technology offers solutions to social problems.[D]Our immediate future is hard to conceive.34.To ensure the future of mankind,it is crucial to[A]draw on our experience from the past.[B]adopt an optimistic view of the world.[C]explore our planet’s abundant resources.[D]curb our ambition to reshape history.35.Which of the following would be the best title for the text?[A]Uncertainty about Our Future[B]Evolution of the Human Species[C]The Ever-bright Prospects of Mankind[D]Science,Technology and HumanityText4①On afive to three vote,the Supreme Court knocked out much of Arizona’s immigration law Monday—a modest policy victory for the Obama Administration.②But on the more important matter of the Constitution,the decision was an8-0defeat for the Administration’s effort to upset the balance of power between the federal government and the states.①In Arizona v.United States,the majority overturned three of the four contested provisions of Arizona’s controversial plan to have state and local police enforce federal immigration law.②The Constitutional principles that Washington alone has the power to“establish a uniform Rule of Naturalization”and that federal laws precede state laws are noncontroversial.③Arizona had attempted to fashion state policies that ran parallel to the existing federal ones.①Justice Anthony Kennedy,joined by Chief Justice John Roberts and the Court’s liberals, ruled that the stateflew too close to the federal sun.②On the overturned provisions the majority held that Congress had deliberately“occupied thefield,”and Arizona had thus intruded on the federal’s privileged powers.①However,the Justices said that Arizona police would be allowed to verify the legal status of people who come in contact with law enforcement.②That’s because Congress has always envisioned joint federal-state immigration enforcement and explicitly encourages state officers to share information and cooperate with federal colleagues.①Two of the three objecting Justices—Samuel Alito and Clarence Thomas—agreed with this Constitutional logic but disagreed about which Arizona rules conflicted with the federal statute.②The only major objection came from Justice Antonin Scalia,who offered an even more robust defense of state privileges going back to the Alien and Sedition Acts.①The8-0objection to President Obama turns on what Justice Samuel Alito describes in his objection as“a shocking assertion of federal executive power”.②The White House argued that Arizona’s laws conflicted with its enforcement priorities,even if state laws complied with federal statutes to the letter.③In effect,the White House claimed that it could invalidate any otherwiselegitimate state law that it disagrees with.①Some powers do belong exclusively to the federal government,and control of citizenship and the borders is among them.②But if Congress wanted to prevent states from using their own resources to check immigration status,it could.③It never did so.④The Administration was in essence asserting that because it didn’t want to carry out Congress’s immigration wishes,no state should be allowed to do so either.⑤Every Justice rightly rejected this remarkable claim.36.Three provisions of Arizona’s plan were overturned because they[A]overstepped the authority of federal immigration law.[B]disturbed the power balance between different states.[C]deprived the federal police of Constitutional powers.[D]contradicted both the federal and state policies.37.On which of the following did the Justices agree,according to Paragraph4?[A]States’independence from federal immigration law.[B]Federal officers’duty to withhold immigrants’information.[C]States’legitimate role in immigration enforcement.[D]Congress’s intervention in immigration enforcement.38.It can be inferred from Paragraph5that the Alien and Sedition Acts[A]violated the Constitution.[B]stood in favor of the states.[C]supported the federal statute.[D]undermined the states’interests.39.The White House claims that its power of enforcement[A]outweighs that held by the states.[B]is established by federal statutes.[C]is dependent on the states’support.[D]rarely goes against state laws.40.What can be learned from the last paragraph?[A]Immigration issues are usually decided by Congress.[B]The Administration is dominant over immigration issues.[C]Justices wanted to strengthen its coordination with Congress.[D]Justices intended to check the power of the Administration.Part BDirections:In the following text,some sentences have been removed.For Questions41-45,choose the most suitable one from the list A-G tofit into each of the numbered blanks.There are two extra choices,which do notfit in any of the blanks.Mark your answers on the ANSWER SHEET.(10 points)The social sciences areflourishing.As of2005,there were almost half a million professional social scientists from allfields in the world,working both inside and outside academia.According to the World Social Science Report2010,the number of social-science students worldwide has swollen by about11%every year since2000.Yet this enormous resource is not contributing enough to today’s global challenges, including climate change,security,sustainable development and health.(41)Humanity has the necessary agro-technological tools to eradicate hunger,from genetically engineered crops to artificial fertilizers.Here,too,the problems are social:the organization and distribution of food, wealth and prosperity.(42)This is a shame—the community should be grasping the opportunity to raise its influence in the real world.To paraphrase the great social scientist Joseph Schumpeter:there is no radical innovation without creative destruction.Today,the social sciences are largely focused on disciplinary problems and internal scholarly debates,rather than on topics with external impact.Analyses reveal that the number of papers including the keywords“environmental change”or“climate change”have increased rapidly since2004.(43)When social scientists do tackle practical issues,their scope is often local:Belgium is interested mainly in the effects of poverty on Belgium,for example.And whether the community’s work contributes much to an overall accumulation of knowledge is doubtful.The problem is not necessarily the amount of available funding.(44)________This is an adequate amount so long as it is aimed in the right direction.Social scientists who complain about a lack of funding should not expect more in today’s economic climate.The trick is to direct these funds better.The European Union Framework funding programs have long had a category specifically targeted at social scientists.This year,it was proposed that the system be changed:Horizon2020,a new program to be enacted in2014,would not have such a category.This has resulted in protests from social scientists.But the intention is not to neglectsocial science;rather,the complete opposite.(45)That should create more collaborative endeavors and help to develop projects aimed directly at solving global problems.[A]It could be that we are evolving two communities of social scientists:one that is discipline-oriented and publishing in highly specialized journals,and one that is problem-oriented and publishing elsewhere,such as policy briefs.[B]However,the numbers are still small:in2010,about1,600of the100,000social-sciencespapers published globally included one of these keywords.[C]The idea is to force social scientists to integrate their work with other categories,includinghealth and demographic change;food security;marine research and the bio-economy;clean, efficient energy;and inclusive,innovative and secure societies.[D]The solution is to change the mindset of the academic community,and what it considers to beits main goal.Global challenges and social innovation ought to receive much more attention from scientists,especially the young ones.[E]These issues all have root causes in human behavior:all require behavioral change and socialinnovations,as well as technological development.Stemming climate change,for example, is as much about changing consumption patterns and promoting tax acceptance as it is about developing clean energy.[F]Despite these factors,many social scientists seem reluctant to tackle such problems.And inEurope,some are up in arms over a proposal to drop a specific funding category for social-science research and to integrate it within cross-cutting topics of sustainable development. [G]During the late1990s,national spending on social sciences and the humanities as a percentageof all research and development funds—including government,higher education,non-profit and corporate—varied from around4%to25%;in most European nations,it is about15%.Part CDirections:Read the following text carefully and then translate the underlined segments into Chinese. Your translation should be written neatly on the ANSWER SHEET.(10points)It is speculated that gardens arise from a basic human need in the individuals who made them: the need for creative expression.There is no doubt that gardens evidence an irrepressible urge to create,express,fashion,and beautify and that self-expression is a basic human urge;(46)yet when one looks at the photographs of the gardens created by the homeless,it strikes one that,for alltheir diversity of styles,these gardens speak of various other fundamental urges,beyond that of decoration and creativeexpression.One of these urges has to do with creating a state of peace in the midst of turbulence,a“still point of the turning world,”to borrow a phrase from T.S.Eliot.(47)A sacred place of peace, however crude it may be,is a distinctly human need,as opposed to shelter,which is a distinctly animal need.This distinction is so much so that where the latter is lacking,as it is for these unlikely gardeners,the former becomes all the more posure is a state of mind made possible by the structuring of one’s relation to one’s environment.(48)The gardens of the homeless,which are in effect homeless gardens,introduce form into an urban environment where it either didn’t exist or was not discernible as such.In so doing they give composure to a segment of the inarticulate environment in which they take their stand.Another urge or need that these gardens appear to respond to,or to arise from,is so intrinsic that we are barely ever conscious of its abiding claims on us.When we are deprived of green,of plants,of trees,(49)most of us give in to a demoralization of spirit which we usually blame on some psychological conditions,until one day wefind ourselves in a garden and feel the oppression vanish as if by magic.In most of the homeless gardens of New York City the actual cultivation of plants is unfeasible,yet even so the compositions often seem to represent attempts to call forth the spirit of plant and animal life,if only symbolically,through a clumplike arrangement of materials, an introduction of colors,small pools of water,and a frequent presence of petals or leaves as well as of stuffed animals.On display here are various fantasy elements whose reference,at some basic level,seems to be the natural world.(50)It is this implicit or explicit reference to nature that fully justifies the use of word garden,though in a“liberated”sense,to describe these synthetic constructions.In them we can see biophilia—a yearning for contact with nonhuman life —assuming uncanny representational forms.Section III WritingPart A51.Directions:Write an e-mail of about100words to a foreign teacher in your college,inviting him/her to be a judge for the upcoming English speech contest.You should include the details you think necessary.You should write neatly on the ANSWER SHEET.Do not sign your own name at the end of the e“Li Ming”instead.Do not write the address.(10points)Part B52.Directions:Write an essay of160-200words based on the following drawing.In your essay,you should1)describe the drawing briefly,2)interpret its intended meaning,and3)give your comments.You should write neatly on the ANSWER SHEET.(20points)2013年英语（一）试题参考答案1.A.grants2.D.objective3.C.picture4.D.For example5.B.fearful6.D.on7.A.if8.A.test9.D.success10. C.chosen11. A.otherwise12. C.conducted13. B.rated14. C.took15. B.then16. C.marked17. D.before18. D.drop19. B.undo20. A.necessary Section I Use of English注：英语一2013年完形第2题在考研大纲解析中给定的答案是objective。
2013年全国硕士研究生入学考试数学一真题答案及解析
1 a 1 2 0 0 【解析】设 A a b a ，B 0 b 0 ，因为 A与 B 为实对称矩阵， 1 a 1 0 0 0
则 A与B 相似的充要条件是 A 的特征值分别为 2,b, 0 ，
1
A的特征方程 E-A a 1
1 /2 1 2 2 1 1 /2 2 1 3 2 sin d r dr 2 2 4 cos d sin d 0 0 0 0 2 0 4 2 0 4 1!! 1 1 1!! 1 11 . 2 2 4 4 2 2!! 2 4 2 2!! 2 4 2 8 8
/2 1 1 cos 2 d sin 2 d 0 4 4
I 3 I 4 故应选 (D). .
高学网教研中心整理
2013年考研真题
高学网权威发布
（5）设 A, B, C 均为 n 阶矩阵，若 AB C ，且 B 可逆，则（ ）. （A）矩阵 C 的行向量组与矩阵 A 的行向量组等价. （B）矩阵 C 的列向量组与矩阵 A 的列向量组等价. （C）矩阵 C 的行向量组与矩阵 B 的行向量组等价. （D）矩阵 C 的列向量组与矩阵 B 的列向量组等价. 【答案】B. 【解析】将 A, C 按列分块，若 A=(1 ,..., n ),C=( 1 ,..., n ) 由于 AB C ，故
a
1
a
1
b
a
a 0 b a 1 0 2a 2
[( b)( 2) 2a 2 ]
因为 0， 2,b 是 A 的特征值，所以 2a 0，即a 0 .
2
当a 0时
2013考研政治真题及答案解析
2013考研政治真题及答案解析(最终版)一、单项选择题：1～16小题，每小题1分，共16分。
下列每题给出的四个选项中，只有一个选项是符合题目要求的。
请在答题卡上将所选项的字母涂黑。
1.有一幅对联，上联“桔子洲，洲旁舟，舟行洲不行，”下联“天心阁，阁中鸽，鸽飞阁不飞。
”这形象的说明了运动和静止是相互依存的静止是：A.运动的普遍状态B.运动的内在原因C.运动的衡量尺度D.运动的存在方式【答案】C【解析】运动和静止是相互统一的关系。
第一，运动和静止互为前提，相互依赖。
相对静止离不开绝对运动，是一定范围内的绝对运动的结果;绝对运动通过相对静止表现出来，并且通过相对静止找到它的量度。
离开相对静止来谈运动，运动也就无从获得自己的规定和衡量自己的尺度。
任何事物相对静止的状况都是它过去的运动所造成的，并且是它将来运动的出发点。
因为物质的多样性和事物的某种状态只有在相对静止中才体现出来，只有了解了事物的相对静止的状况，才能清楚地了解它过去的运动，预测它将来可能发生的变化，才能区别千差万别的具体事物，并对其进行研究。
第二，运动和静止相互渗透、相互包含。
在绝对运动中有相对静止，在相对静止中又有绝对运动。
任何事物都是绝对运动和相对静止的辩证统一。
2.一位机械工程专家讲过这样一件事：“文革”中，他在农场劳动，有一天领导要他去割羊草，他没养过羊，怎么认得羊草呢?但脑子一转办法就来了，他把羊都赶去看羊吃什么就割什么。
不到半天就割回了羊草。
这位专家之所以这样做是因为他意识到“羊吃草”与“割羊草”两者之间存在：A.主观联系B.必然联系C.因果联系D.本质联系【答案】D【解析】本题是考查唯物辩证法的联系观。
"羊吃草"与"割羊草"之间的关系不是因果联系，因为"羊吃草"不必然引起"割羊草"，AB错误;C选项表述错误，联系是客观的;看羊吃什么就割什么，这体现的就是本质联系，D为正确答案。
2013年考研数学二真题及答案解析
方法二：
Q 第二象限中 y > 0 ， x < 0 ，始终 y > x
即 y−x>0
∴ I 2 >0 ∴ 选（B）.
（ ）
(7) 设 A， B， C 均为 n 阶矩阵， 若 AB = C ， 且 B 可逆， 则 (A) 矩阵 C 的行向量组与矩阵 A 的行向量等价 (B) 矩阵 C 的列向量组与矩阵 A 的列向量等价 (C) 矩阵 C 的行向量组与矩阵 B 的行向量等价 (D) 矩阵 C 的列向量组与矩阵 B 的列向量等价 【答案】(B) 【解析】将 A, C 按列分块， A = (α1 ,..., α n ), C = (γ 1 ,..., γ n ) 由于 AB = C ，故
2 n
) （A）
（D）-2
【解析】因为 x = 0时，y = 1 即 f (0) = 1 .
2 Q lim n f ( ) − 1 = lim 2⋅ n →∞ n n →∞
又Q cos( xy ) + ln y − x = 1
2 f ( ) − f (0) n = 2 f '(0) = 2 y ' x = 0 2 −0 n
（6）设 Dk 是圆域 D = ( x, y ) | x 2 + y 2 ≤ 1 在第 k 象限的部分，记 I k =
{
}
∫∫ ( y − x)dxdy ,
Dk
(k = 1, 2,3, 4) 则
(A)
（ (B) I 2 > 0 (C) I 3 > 0 (D) I 4 > 0
）
I1 > 0
【答案】 （B） 【解析】方法一：
∫
e
1
（5）设 z =
2013考研数学一真题及答案解析
由于 AB = C ,故
(α1,
...,α
n
)
b11 . bn1
... ... ...
b1n . bnn
=
(γ
1
,
...,
γ
n
)
即 γ1 = b11α1 + ... + bn1αn ,...,γ n = b1nα1 + ... + bnnαn 即 C 的列向量组可由 A 的列向量线性表示 由于 B 可逆，故 A = CB−1 ， A 的列向量组可由 C 的列向量组线性表示，选 B
【答案】A
【解析】曲面在点 (0,1,-1) 处的法向量为
→
n =(Fx′,Fy′,Fz′) (0,1,-1) =(2x-y sin (xy)+1,-x sin (xy)+z,y) (0,1,-1) =(1,-1,1) 故曲面在点 (0,1,-1) 处的切面方程为 1⋅ (x-0)-(y-1)+(z+1)=0, 即 x − y + z = −2 ，选 A
1 dx
=
1 cos t
,
d2y dx2
t=π 4
=
1 cos
π
=
2
dt
4
∫ (12)
+∞ 1
ln (1 +
x x)2
dx
=
.
【答案】 ln 2
∫ ∫ 【解析】
+∞ 1
ln (1 +
x x)2
dx
=
−
ln (1 +
x x)
+∞ 1
+
+∞ dx = ln x 1 x(1+ x) (1+ x)
2013年考研数三真题及答案解析(完整版)
2013年考研数三真题及答案解析一、选择题 1—8小题．每小题4分，共32分．、１．当0→x 时，用)(x o 表示比x 高阶的无穷小，则下列式子中错误的是（ ）（A ）)()(32x o x o x =⋅ （B ）)()()(32x o x o x o = （C ）)()()(222x o x o x o =+ （D ）)()()(22x o x o x o =+【详解】由高阶无穷小的定义可知（A ）（B ）（C ）都是正确的，对于（D ）可找出反例，例如当0→x 时)()(),()(2332x o x x g x o x x x f ===+=，但)()()(x o x g x f =+而不是)(2x o 故应该选（D ）．2．函数xx x x x f xln )1(1)(+-=的可去间断点的个数为（ ）（A ）0 （B ）1 （C ）2 （D ）3 【详解】当0ln →x x 时，x x ex xx xln ~11ln -=-，1ln ln limln )1(1lim)(lim 0==+-=→→→x x x x x x x x x f x xx x ，所以0=x 是函数)(x f 的可去间断点．21ln 2ln limln )1(1lim)(lim 011==+-=→→→xx xx xx x x x f x xx x ，所以1=x 是函数)(x f 的可去间断点． ∞=+-=+-=-→-→-→xx x x xx x x x f x x x x ln )1(ln limln )1(1lim)(lim 111，所以所以1-=x 不是函数)(x f 的可去间断点．故应该选（C ）．３．设k D 是圆域{}1|),(22≤+=y x y x D 的第k 象限的部分，记⎰⎰-=kD k dxdy x y I )(，则（ ）（A ）01>I （B ）02>I （C ）03>I （D ）04>I 【详解】由极坐标系下二重积分的计算可知()ππππππθθθθθθθθ22122110222)1(|cos sin 31)sin (sin 31)cos (sin )(k k kk k k D k d dr r d dxdy x y I k ---+-=-=-=-=⎰⎰⎰⎰⎰所以ππ32,32,04231-====I I I I ，应该选（B ）． ４．设{}n a 为正项数列，则下列选择项正确的是（ ） （A ）若1+>n n a a ，则∑∞=--11)1(n n n a 收敛；（B ）若∑∞=--11)1(n n n a 收敛，则1+>n n a a ； （C ）若∑∞=1n na收敛．则存在常数1>P ，使n pn a n ∞→lim 存在；（D ）若存在常数1>P ，使n pn a n ∞→lim 存在，则∑∞=1n na收敛．【详解】由正项级数的比较审敛法，可知选项（D ）正确，故应选（Ｄ）．此小题的（A ）（B ）选项想考查的交错级数收敛的莱布尼兹条件，对于选项（A ），但少一条件0lim =∞→n n a ，显然错误．而莱布尼兹条件只是交错级数收敛的充分条件，不是必要条件，选项（B ）也不正确，反例自己去构造．５．设Ａ，Ｂ，Ｃ均为n 阶矩阵，若ＡＢ＝Ｃ，且Ｂ可逆，则（A ）矩阵C 的行向量组与矩阵A 的行向量组等价． （B ）矩阵C 的列向量组与矩阵A 的列向量组等价． （C ）矩阵C 的行向量组与矩阵B 的行向量组等价． （D ）矩阵C 的列向量组与矩阵B 的列向量组等价．【详解】把矩阵A ，C 列分块如下：()()n n C A γγγααα,,,,,,,2121 ==，由于ＡＢ＝Ｃ，则可知),,2,1(2211n i b b b n in i i i =+++=αααγ，得到矩阵C 的列向量组可用矩阵A 的列向量组线性表示．同时由于B 可逆，即1-=CB A ，同理可知矩阵A 的列向量组可用矩阵C 的列向量组线性表示，所以矩阵C 的列向量组与矩阵A 的列向量组等价．应该选（B ）．6．矩阵⎪⎪⎪⎭⎫ ⎝⎛1111a a b a a 与矩阵⎪⎪⎪⎭⎫ ⎝⎛00000002b 相似的充分必要条件是（A ）2,0==b a （B ）0=a ，b 为任意常数 （C ）0,2==b a （D ）2=a ，b 为任意常数【详解】注意矩阵⎪⎪⎪⎭⎫ ⎝⎛00000002b 是对角矩阵，所以矩阵A=⎪⎪⎪⎭⎫ ⎝⎛1111a a b a a 与矩阵⎪⎪⎪⎭⎫ ⎝⎛00000002b 相似的充分必要条件是两个矩阵的特征值对应相等．)22)2((111122a b b aa baa A E -++--=---------=-λλλλλλλ从而可知b a b 2222=-，即0=a ，b 为任意常数，故选择（B ）．7．设321,,X X X 是随机变量，且)3,5(~),2,0(~),1,0(~23221N X N X N X ，{}22≤≤-=i i X P P ，则（A ）321P P P >> （B ）312P P P >> （C ）123P P P >> （D ）231P P P >> 【详解】若),(~2σμN X ，则)1,0(~N X σμ-1)2(21-Φ=P ，{}1)1(212122222-Φ=⎭⎬⎫⎩⎨⎧≤≤-=≤≤-=X P X P P ， {}())13737)1(3523535222333Φ-⎪⎭⎫⎝⎛Φ=⎪⎭⎫ ⎝⎛-Φ--Φ=⎭⎬⎫⎩⎨⎧-≤-≤--=≤≤-=X P X P P ，=-23P P 0)1(32)1(3371<Φ-<Φ-⎪⎭⎫⎝⎛Φ+．故选择（A ）．8．设随机变量X 和Y 相互独立，且X 和Y 的概率分布分别为X 0 1 2 3P P1/21/41/81/8Y -1 0 1 P1/31/31/3则{}==+2Y X P （ ） （A ）121 （B ）81 （C ）61 （D ）21 【详解】{}{}{}{}612412411211,30,21,12=++=-==+==+====+Y X P Y X P Y X P Y X P ，故选择（C ）．二、填空题（本题共6小题，每小题4分，满分24分. 把答案填在题中横线上）9．设曲线)(x f y =和x x y -=2在点()0,1处有切线，则=⎪⎭⎫⎝⎛+∞→2lim n n nf n ． 【详解】由条件可知()1)1(',01==f f ．所以2)1('22222)1(221lim 2lim -=-=-+⋅+--⎪⎭⎫ ⎝⎛+-+=⎪⎭⎫ ⎝⎛+∞→∞→f nn n f n f n n nf n n 10．设函数()y x z z ,=是由方程()xy y z x=+确定，则=∂∂)2,1(|xz． 【详解】 设()xyy z z y x F x -+=)(,,，则()1)(),,(,)l n ()(,,-+=-++=x z x x y z x z y x F y y z y z z y x F ，当2,1==y x 时，0=z ，所以2ln 22|)2,1(-=∂∂xz． 11．=+⎰∞+x d x x12)1(ln ．【详解】2ln |1ln )1(1|1ln 11ln )1(ln 111112=+=+++-=+-=+∞+∞+∞+∞+∞+⎰⎰⎰x x dx x x x x x xd x d x x 12．微分方程041=+'-''y y y 的通解为 ． 【详解】方程的特征方程为041=+-λλr，两个特征根分别为2121==λλ，所以方程通解为221)(xex C C y +=，其中21,C C 为任意常数．13．设()ij a A =是三阶非零矩阵，A 为其行列式，ij A 为元素ij a 的代数余子式，且满足)3,2,1,(0==+j i a A ij ij ，则A = ．【详解】由条件)3,2,1,(0==+j i a A ij ij 可知0*=+TA A ，其中*A 为A 的伴随矩阵，从而可知A AA A T -===-13**，所以A 可能为1-或0．但由结论⎪⎩⎪⎨⎧-<-===1)(,01)(,1)(,)(*n A r n A r n A r n A r 可知，0*=+TA A 可知*)()(A r A r =,伴随矩阵的秩只能为3，所以.1-=A14．设随机变量X 服从标准正分布)1,0(~N X ，则()=X Xe E 2 ． 【详解】()=X Xe E 2dx ex edx ex dx exe x x x x⎰⎰⎰∞+∞---∞+∞-+--∞+∞--+-==2)2(222)2(22222)22(2221πππ22222222)(2222e e X E e dt e dt te e t t =+=⎪⎪⎭⎫ ⎝⎛+=⎰⎰∞+∞--∞+∞--π． 所以为22e ．三、解答题15．（本题满分10分）当0→x 时，x x x 3cos 2cos cos 1-与nax 是等价无穷小，求常数n a ,．【分析】主要是考查0→x 时常见函数的马克劳林展开式． 【详解】当→x 时，)(211co s 22x o x x +-=，)(21)()2(2112cos 2222x o x x o x x +-=+-=，)(291)()3(2113cos 2222x o x x o x x +-=+-=，所以)(7))(291))((21))((211(13cos 2cos cos 122222222x o x x o x x o x x o x x x x +=+-+-+--=-，由于x x x 3cos 2cos cos 1-与nax 是等价无穷小，所以2,7==n a ．16．（本题满分10分） 设D 是由曲线3x y =，直线a x =)0(>a 及x 轴所转成的平面图形，y x V V ,分别是D 绕x轴和y 轴旋转一周所形成的立体的体积，若y x V V =10，求a 的值． 【详解】由微元法可知πππ35320253a dx x dx y V a a x ===⎰⎰；πππ37340762)(2a dx x dx x xf V a ay ===⎰⎰；由条件y x V V =10，知77=a ． 17．（本题满分10分）设平面区域D 是由曲线8,3,3=+==y x x y y x 所围成，求⎰⎰Ddxdy x 2． 【详解】341683622332222221=+=+=⎰⎰⎰⎰⎰⎰⎰⎰⎰⎰-xx xx D D Ddy dx x dy dx x dxdy x dxdy x dxdy x ． 18．（本题满分10分）设生产某产品的固定成本为6000元，可变成本为20元/件，价格函数为,100060QP -=（P 是单价，单位：元，Q 是销量，单位：件），已知产销平衡，求： （1）该的边际利润．（2）当P=50时的边际利润，并解释其经济意义． （3）使得利润最大的定价P ． 【详解】（1）设利润为y ，则6000100040)206000(2--=+-=Q Q Q PQ y ， 边际利润为.50040'Q y -= （2）当P=50时，Q=10000，边际利润为20．经济意义为：当P=50时，销量每增加一个，利润增加20． （3）令0'=y ，得.40100002000060,20000=-==P Q19．（本题满分10分）设函数()x f 在),0[+∞上可导，()00=f ，且2)(lim =+∞→x f x ，证明（1）存在0>a ，使得();1=a f（2）对（1）中的a ，存在),0(a ∈ξ，使得af 1)('=ξ． 【详解】证明（1）由于2)(lim =+∞→x f x ，所以存在0>X ，当X x >时，有25)(23<<x f ， 又由于()x f 在),0[+∞上连续，且()00=f ，由介值定理，存在0>a ，使得();1=a f （2）函数()x f 在],0[a 上可导，由拉格朗日中值定理， 存在),0(a ∈ξ，使得aa f a f f 1)0()()('=-=ξ．20．（本题满分11分） 设⎪⎪⎭⎫⎝⎛=⎪⎪⎭⎫⎝⎛=b B a A 110,011，问当b a ,为何值时，存在矩阵C ，使得B CA AC =-，并求出所有矩阵C ．【详解】显然由B CA AC =-可知，如果C 存在，则必须是2阶的方阵．设⎪⎪⎭⎫ ⎝⎛=4321x xx x C ， 则B CA AC =-变形为⎪⎪⎭⎫⎝⎛=⎪⎪⎭⎫ ⎝⎛---++-+-b ax x xx x ax x ax ax x 1103243142132， 即得到线性方程组⎪⎪⎩⎪⎪⎨⎧=-=--=++-=+-bax x x x x ax x ax ax x 3243142132110，要使C 存在，此线性方程组必须有解，于是对方程组的增广矩阵进行初等行变换如下()⎪⎪⎪⎪⎪⎭⎫⎝⎛+---→⎪⎪⎪⎪⎪⎭⎫⎝⎛-----=b a a b a aa ab A 000010000001011101010111011010010|， 所以，当0,1=-=b a 时，线性方程组有解，即存在矩阵C ，使得B CA AC =-．此时，()⎪⎪⎪⎪⎪⎭⎫⎝⎛--→00000000000011011101|b A ， 所以方程组的通解为⎪⎪⎪⎪⎪⎭⎫⎝⎛+⎪⎪⎪⎪⎪⎭⎫ ⎝⎛-+⎪⎪⎪⎪⎪⎭⎫ ⎝⎛=⎪⎪⎪⎪⎪⎭⎫ ⎝⎛=100101110001214321C C x x x x x ，也就是满足B CA AC =-的矩阵C 为⎪⎪⎭⎫⎝⎛-++=211211C C C C C C ，其中21,C C 为任意常数．21．（本题满分11分） 设二次型23322112332211321)()(2),,(x b x b x b x a x a x a x x x f +++++=．记⎪⎪⎪⎭⎫ ⎝⎛=⎪⎪⎪⎭⎫ ⎝⎛=321321,b b b a a a βα．（1）证明二次型f 对应的矩阵为 T T ββαα+2；（2）若βα,正交且为单位向量，证明f 在正交变换下的标准形为 22212y y +． 【详解】证明：（1）()()()()()()()()()()⎪⎪⎪⎭⎫ ⎝⎛+=⎪⎪⎪⎭⎫ ⎝⎛+⎪⎪⎪⎭⎫⎝⎛=⎪⎪⎪⎭⎫⎝⎛⎪⎪⎪⎭⎫ ⎝⎛+⎪⎪⎪⎭⎫ ⎝⎛⎪⎪⎪⎭⎫ ⎝⎛=+++++=321321321321321321321321321321321321321321233221123322113212,,,,2,,,,,,,,,,2)()(2),,(x x x x x x x x x x x x x x x x x x x x x b b b b b b x x x x x x a a a a a a x x x x b x b x b x a x a x a x x x f TT TT ββααββαα所以二次型f 对应的矩阵为 T T ββαα+2．证明（2）设=A T T ββαα+2，由于0,1==αβαT 则()ααββαααββααα2222=+=+=T T TA ，所以α为矩阵对应特征值21=λ的特征向量；()ββββααβββααβ=+=+=222T T T A ，所以β为矩阵对应特征值12=λ的特征向量；而矩阵A 的秩2)()2()2()(=+≤+=T T T T r r r A r ββααββαα，所以03=λ也是矩阵的一个特征值．故f 在正交变换下的标准形为 22212y y +． 22．（本题满分11分）设()Y X ,是二维随机变量，X 的边缘概率密度为⎩⎨⎧<<=其他,010,3)(2x x x f X ，在给定)10(<<=x x X 的条件下，Y 的条件概率密度为⎪⎩⎪⎨⎧<<=其他,0,0,3)/(32x y x y x y f XY ． （1）求()Y X ,的联合概率密度()y x f ,； （2）Y 的的边缘概率密度)(y f Y ．【详解】（1）()Y X ,的联合概率密度()y x f ,：()⎪⎩⎪⎨⎧<<<<=⋅=其他,00,10,9)()/(,2x y x xy x f x y f y x f X XY （2）Y 的的边缘概率密度)(y f Y ：⎪⎩⎪⎨⎧<<-===⎰⎰∞+∞-其他,010,ln 99),()(212y y y dx x y dx y x f y f yY 23．（本题满分11分）设总体X 的概率密度为⎪⎩⎪⎨⎧>=-其他,00,);(32x e x x f x θθθ，其中θ为为未知参数且大于零，n X X X ,21为来自总体X 的简单随机样本．（1）求θ的矩估计量； （2）求θ的极大似然估计量．【详解】（1）先求出总体的数学期望E （X ）θθθ===⎰⎰∞+-∞+∞-022)()(dx e xdx x xf X E x ，令∑===n n i X n X X E 11)(，得θ的矩估计量∑=∧==ni i X n X 11θ．（2）当),2,1(0n i x i =>时，似然函数为⎪⎪⎭⎫⎝⎛-==-∑⎪⎪⎭⎫ ⎝⎛=⎪⎪⎭⎫ ⎝⎛==∏∏ni i ix n i i n ni x iex e x L 11312132)(θθθθθ， 取对数，∑∑==-⎪⎪⎭⎫ ⎝⎛-=ni i n i i x xn L 11ln 31ln 2)(ln θθθ，令0)(ln =θθd L d ，得0121=-∑=n i ix n θ， 解得的极大似然估计量为．。
2013年考研英语一真题及答案(清晰完整干净版)
2013年全国硕士研究生入学统一考试英语一试题Section I Use of EnglishDirections:Read the following text. Choose the best word(s) for each numbered blank and mark A, B, C or D on ANSWER SHEET 1. (10 points)People are, on the whole, poor at considering background information when making individual decisions. At first glance this might seem like a strength that 1the ability to make judgments which are unbiased by 2factors. ButDr. Uri Simonsohn speculated that an inability to consider the big 3was leading decision-makers to be biased by the daily samples of information they were working with. 4, he theorised that a judge 5of appearing too soft 6crime might be more likely to send someone to prison 7he had already sentenced five or six other defendants only to forced community service on that day.To 8this idea, he turned to the university-admissions process. In theory,the 9of an applicant should not depend on the few others 10 randomly for interview during the same day, but Dr. Simonsohn suspected the truth was 11.He studied the results of 9,323 MBA interviews 12by 31 admissionsofficers. The interviewers had 13applicants on a scale of one to five. Thisscale 14numerous factors into consideration. The scores were 15 used in conjunction with an applicant's score on the Graduate Management Admission Test, or GMAT, a standardized exam which is 16out of 800 points, to make a decision on whether to accept him or her.Dr. Simonsohn found if the score of the previous candidate in a daily series of interviewees was 0.75 points or more higher than that of the one 17that, thenthe score for the next applicant would 18by an average of 0.075 points. This might sound small, but to 19the effects of such a decrease a candidate would need 30 more GMAT points than would otherwise have been 20.1. [A] grants [B] submits [C] transmits [D] delivers]2. [A] minor [B] objective [C] crucial [D] external3. [A] issue [B] vision [C] picture [D] moment4. [A] For example [B] On average [C] In principle [D] Above all5. [A] fond [B] fearful [C] capable [D] thoughtless6. [A] in [B] on [C] to [D] for7. [A] if [B] until [C] though [D] unless8. [A] promote [B] emphasize [C] share [D] test9. [A] decision [B] quality [C] status [D] success10. [A] chosen [B] studied [C] found [D] identified11. [A] exceptional [B] defensible [C] replaceable [D] otherwise12. [A] inspired [B] expressed [C] conducted [D] secured13. [A] assigned [B] rated [C] matched [D] arranged14. [A] put [B] got [C] gave [D] took15. [A] instead [B] then [C] ever [D] rather16. [A] selected [B] passed [C] marked [D] introduced17. [A] before [B] after [C] above [D] below18. [A] jump [B] float [C] drop [D] fluctuate19. [A] achieve [B] undo [C] maintain [D] disregard20. [A] promising [B] possible [C] necessary [D] helpfulSection II Reading ComprehensionPart ADirections:Read the following four texts. Answer the questions below each text by choosing A, B, C or D. Mark your answers on ANSWER SHEET 1. (40 points)Text 1In the 2006 film version of The Devil Wears Prada, Miranda Priestly, played by Meryl Streep, scolds her unattractive assistant for imagining that high fashion doesn't affect her. Priestly explains how the deep blue color of the assistant's sweater descended over the years from fashion shows to department stores and to the bargain bin in which the poor girl doubtless found her garment.This top-down conception of the fashion business couldn't be more out of date or at odds with the feverish world described in Overdressed, Elizabeth Cline's three-year indictment of "fast fashion." In the last decade or so, advances in technology have allowed mass-market labels such as Zara, H&M, and Uniqlo to react to trends more quickly and anticipate demand more precisely. Quicker turnarounds mean less wasted inventory, more frequent release, and more profit. These labels encourage style-conscious consumers to see clothes as disposable—meant to last only a wash or two, although they don't advertise that—and to renew their wardrobe every few weeks. By offering on-trend items at dirt-cheap prices, Cline argues, these brands have hijacked fashion cycles, shaking an industry long accustomed to a seasonal pace.The victims of this revolution, of course, are not limited to designers. For H&M to offer a $5.95 knit miniskirt in all its 2,300-plus stores around the world, it must rely on low-wage overseas labor, order in volumes that strain natural resources, and use massive amounts of harmful chemicals.Overdressed is the fashion world's answer to consumer-activist bestsellers like Michael Pollan's The Omnivore's Dilemma. "Mass-produced clothing, like fast food, fills a hunger and need, yet is non-durable and wasteful," Cline argues. Americans, she finds, buy roughly 20 billion garments a year—about 64 items per person—and no matter how much they give away, this excess leads to waste.Towards the end of Overdressed, Cline introduced her ideal, a Brooklyn woman named Sarah Kate Beaumont, who since 2008 has made all of her own clothes—and beautifully. But as Cline is the first to note, it took Beaumont decades to perfect her craft; her example can't be knocked off.Though several fast-fashion companies have made efforts to curb their impacton labor and the environment—including H&M, with its green Conscious Collection line—Cline believes lasting change can only be effected by the customer. She exhibits the idealism common to many advocates of sustainability, be it in food or in energy. Vanity is a constant; people will only start shopping more sustainably when they can't afford not to.21. Priestly criticizes her assistant for her[A] poor bargaining skill.[B] insensitivity to fashion.[C] obsession with high fashion.[D] lack of imagination.22. According to Cline, mass-market labels urge consumers to[A] combat unnecessary waste.[B] shut out the feverish fashion world.[C] resist the influence of advertisements.[D] shop for their garments more frequently.23. The word "indictment" (Line 3, Para. 2) is closest in meaning to[A] accusation.[B] enthusiasm.[C] indifference.[D] tolerance.24. Which of the following can be inferred from the last paragraph?[A] Vanity has more often been found in idealists.[B] The fast fashion industry ignores sustainability.[C] People are more interested in unaffordable garments.[D] Pricing is vital to environment-friendly purchasing.25. What is the subject of the text?[A] Satire on an extravagant lifestyle.[B] Challenge to a high-fashion myth.[C] Criticism of the fast-fashion industry.[D] Exposure of a mass-market secret.Text 2An old saying has it that half of all advertising budgets are wasted—the troubleis, no one knows which half. In the internet age, at least in theory, this fraction can be much reduced. By watching what people search for, click on and say online, companies can aim "behavioural" ads at those most likely to buy.In the past couple of weeks a quarrel has illustrated the value to advertisers of such fine-grained information: Should advertisers assume that people are happy to be tracked and sent behavioural ads? Or should they have explicit permission?In December 2010 America's Federal Trade Commission (FTC) proposed adding a "do not track" (DNT) option to internet browsers, so that users could tell advertisers that they did not want to be followed. Microsoft's Internet Explorer and Apple's Safari both offer DNT; Google's Chrome is due to do so this year. In February the FTC and Digital Advertising Alliance (DAA) agreed that the industry would get cracking on responding to DNT requests.On May 31st Microsoft set off the row. It said that Internet Explorer 10, the version due to appear with windows 8, would have DNT as a default. Advertisers are horrified. Human nature being what it is, most people stick with default settings. Few switch DNT on now, but if tracking is off it will stay off. Bob Liodice, the chief executive of the Association of National Advertisers, one of the groups in the DAA, says consumers will be worse off if the industry cannot collect information about their preferences. People will not get fewer ads, he says. "They'll get less meaningful, less targeted ads."It is not yet clear how advertisers will respond. Getting a DNT signal does not oblige anyone to stop tracking, although some companies have promised to do so. Unable to tell whether someone really objects to behavioural ads or whether they are sticking with Microsoft's default, some may ignore a DNT signal and press on anyway.Also unclear is why Microsoft has gone it alone. After all, it has an ad business too, which it says will comply with DNT requests, though it is still working out how. If it is trying to upset Google, which relies almost wholly on advertising, it has chosen an indirect method: there is no guarantee that DNT by default will become the norm. DNT does not seem an obviously huge selling point for windows 8—though the firm has compared some of its other products favourably with Google's on that count before. Brendon Lynch, Microsoft's chief privacy officer, blogged: "we believe consumers should have more control." Could it really be that simple?26. It is suggested in paragraph 1 that "behavioural" ads help advertisers to:[A] ease competition among themselves[B] lower their operational costs[C] avoid complaints from consumers[D] provide better online services27. "The industry" (Line 6, Para. 3) refers to:[A] online advertisers[B] e-commerce conductors[C] digital information analysis[D] internet browser developers28. Bob Liodice holds that setting DNT as a default[A] many cut the number of junk ads.[B] fails to affect the ad industry.[C] will not benefit consumers.[D] goes against human nature.29. Which of the following is true according to Paragraph 6?[A] DNT may not serve its intended purpose.[B] Advertisers are willing to implement DNT.[C] DNT is losing its popularity among consumers.[D] Advertisers are obliged to offer behavioural ads.30. The author's attitude towards what Brendon Lynch said in his blog is one of[A] indulgence.[B] understanding.[C] appreciation.[D] skepticism.Text 3Up until a few decades ago, our visions of the future were largely - though by no means uniformly - glowingly positive. Science and technology would cure all the ills of humanity, leading to lives of fulfillment and opportunity for all.Now utopia has grown unfashionable, as we have gained a deeper appreciation of the range of threats facing us, from asteroid strike to pandemic flu to climate change. You might even be tempted to assume that humanity has little future to look forward to.But such gloominess is misplaced. The fossil record shows that many species have endured for millions of years – so why shouldn't we? Take a broader look at our species' place in the universe, and it becomes clear that we have an excellent chance of surviving for tens, if not hundreds, of thousands of years (see "100,000 AD: Living in the deep future"). Look up Homo sapiens in the IUCN's "Red List" of threatened species, and you will read: "Listed as Least Concern as the species is very widely distributed, adaptable, currently increasing, and there are no major threats resulting in an overall population decline."So what does our deep future hold? A growing number of researchers and organisations are now thinking seriously about that question. For example, the Long Now Foundation, based in San Francisco, has created a forum where thinkers and scientists are invited to project the implications of their ideas over very long timescales. Its flagship project is a mechanical clock, buried deep inside a mountain in Texas, that is designed to still be marking time thousands of years hence.Then there are scientists who are giving serious consideration to the idea that we should recognise a new geological era: the Anthropocene. They, too, are pulling the camera right back and asking what humanity's impact will be on the planet – in the context of stratigraphic time.Perhaps perversely, it may be easier to think about such lengthy timescales than about the more immediate future. The potential evolution of today's technology, and its social consequences, is dazzlingly complicated, and it's perhaps best left to science-fiction writers and futurologists to explore the many possibilities we can envisage. That's one reason why we have launched Arc, a new publication dedicated to the near future.But take a longer view and there is a surprising amount that we can say with considerable assurance. As so often, the past holds the key to the future: we have now identified enough of the long-term patterns shaping the history of the planet, and our species, to make evidence-based forecasts about the situations in which our descendants will find themselves.This long perspective makes the pessimistic view of our prospects seem more likely to be a passing fad. To be sure, the future is not all rosy: while our species may flourish, a great many individuals may not. But we are now knowledgeable enough to mitigate many of the risks that threatened the existence of earlier humans, and to improve the lot of those to come. Thinking about our place in deep time is a good way to focus on the challenges that confront us today, and to make a future worth living in.31. Our vision of the future used to be inspired by[A] our desire for lives of fulfillment.[B] our faith in science and technology.[C] our awareness of potential risks.[D] our belief in equal opportunity.32. The IUCN's "Red List" suggest that human beings are[A] a sustained species.[B] the world's dominant power.[C] a threat to the environment.[D] a misplaced race.33. Which of the following is true according to Paragraph 5?[A] Arc helps limit the scope of futurological studies.[B] Technology offers solutions to social problem.[C] The interest in science fiction is on the rise.[D] Our immediate future is hard to conceive.34. To ensure the future of mankind, it is crucial to[A] explore our planet's abundant resources.[B] adopt an optimistic view of the world.[C] draw on our experience from the past.[D] curb our ambition to reshape history.35. Which of the following would be the best title for the text?[A] Uncertainty about Our Future.[B] Evolution of the Human Species.[C] The Ever-bright Prospects of Mankind.[D] Science, Technology and Humanity.Text 4On a five to three vote, the Supreme Court knocked out much of Arizona's immigration law Monday—a modest policy victory for the Obama Administration. But on the more important matter of the Constitution, the decision was an 8-0 defeat for the Administration's effort to upset the balance of power between the federal government and the states.In Arizona v. United States, the majority overturned three of the four contested provisions of Arizona's controversial plan to have state and local police enforce federal immigration law. The Constitutional principles that Washington alone has the power to "establish a uniform Rule of Naturalization" and that federal laws precede state laws are noncontroversial. Arizona had attempted to fashion state policies that ran parallel to the existing federal ones.Justice Anthony Kennedy, joined by Chief Justice John Roberts and the Court's liberals, ruled that the state flew too close to the federal sun. On the overturned provisions the majority held the congress had deliberately "occupied the field" and Arizona had thus intruded on the federal's privileged powers.However, the Justices said that Arizona police would be allowed to verify the legal status of people who come in contact with law enforcement. That's because Congress has always envisioned joint federal-state immigration enforcement and explicitly encourages state officers to share information and cooperate with federal colleagues.Two of the three objecting Justice –Samuel Alito and Clarence Thomas –agreed with this Constitutional logic but disagreed about which Arizona rules conflicted with the federal statute. The only major objection came from Justice Antonin Scalia, who offered an even more robust defense of state privileges going back to the Alien and Sedition Acts.The 8-0 objection to President Obama turns on what Justice Samuel Alito describes in his objection as "a shocking assertion of federal executive power." The White House argued that Arizona's laws conflicted with its enforcement priorities, even if state laws complied with federal statutes to the letter. In effect, the White House claimed that it could invalidate any otherwise legitimate state law that it disagrees with.Some powers do belong exclusively to the federal government, and control of citizenship and the borders is among them. But if Congress wanted to prevent states from using their own resources to check immigration status, it could. It never did so. The administration was in essence asserting that because it didn't want to carry out Congress's immigration wishes, no state should be allowed to do so either. Every Justice rightly rejected this remarkable claim.36. Three provisions of Arizona's plan were overturned because they[A] deprived the federal police of Constitutional powers.[B] disturbed the power balance between different states.[C] overstepped the authority of federal immigration law.[D] contradicted both the federal and state policies.37. On which of the following did the Justices agree, according to Paragraph 4?[A] Federal officers' duty to withhold immigrants' information.[B] States' independence from federal immigration law.[C] States' legitimate role in immigration enforcement.[D] Congress's intervention in immigration enforcement.38. It can be inferred from Paragraph 5 that the Alien and Sedition Acts[A] violated the Constitution.[B] undermined the states' interests.[C] supported the federal statute.[D] stood in favor of the states.39. The White House claims that its power of enforcement[A] outweighs that held by the states.[B] is dependent on the states' support.[C] is established by federal statutes.[D] rarely goes against state laws.40. What can be learned from the last paragraph?[A] Immigration issues are usually decided by Congress.[B] Justices intended to check the power of the Administration.[C] Justices wanted to strengthen its coordination with Congress.[D] The Administration is dominant over immigration issues.Part BDirections:In the following article, some sentences have been removed. For Questions 41-45, choose the most suitable one from the list A-G to fit into each of the numbered blank. There are two extra choices, which do not fit in any of the gaps. Mark your answers on ANSWER SHEET 1. (10 points)The social sciences are flourishing. As of 2005, there were almost half a million professional social scientists from all fields in the world, working both inside and outside academia. According to the World Social Science Report 2010, the number of social-science students worldwide has swollen by about 11% every year since 2000.Yet this enormous resource is not contributing enough to today's global challenges including climate change, security, sustainable development and health.(41)Humanity has the necessary agro-technological tools to eradicate hunger, from genetically engineered crops to artificial fertilizers. Here, too, the problems are social: the organization and distribution of food, wealth and prosperity.(42)This is a shame—the community should be grasping the opportunity to raise its influence in the real world. To paraphrase the great social scientist Joseph Schumpeter: there is no radical innovation without creative destruction.Today, the social sciences are largely focused on disciplinary problems and internal scholarly debates, rather than on topics with external impact.Analyses reveal that the number of papers including the keywords "environmental changed" or "climate change" have increased rapidly since 2004, (43) When social scientists do tackle practical issues, their scope is often local: Belgium is interested mainly in the effects of poverty on Belgium for example. And whether the community's work contributes much to an overall accumulation of knowledge is doubtful.The problem is not necessarily the amount of available funding (44)This is an adequate amount so long as it is aimed in the right direction. Socialscientists who complain about a lack of funding should not expect more in today's economic climate.The trick is to direct these funds better. The European Union Framework funding programs have long had a category specifically targeted at social scientists. This year, it was proposed that system be changed: Horizon 2020, a new program to be enacted in 2014, would not have such a category. This has resulted in protests from social scientists. But the intention is not to neglect social science; rather, the complete opposite. (45)That should create more collaborative endeavors and help to develop projects aimed directly at solving global problems.[A] It could be that we are evolving two communities of social scientists: one that is discipline-oriented and publishing in highly specialized journals, and one that is problem-oriented and publishing elsewhere, such as policy briefs.[B] However, the numbers are still small: in 2010, about 1,600 of the 100,000 social-sciences papers published globally included one of these Keywords.[C] The idea is to force social to integrate their work with other categories, including health and demographic change food security, marine research and the bio-economy, clear, efficient energy; and inclusive, innovative and secure societies.[D] The solution is to change the mindset of the academic community, and what it considers to be its main goal. Global challenges and social innovation ought to receive much more attention from scientists, especially the young ones.[E] These issues all have root causes in human behavior. All require behavioral change and social innovations, as well as technological development. Stemming climate change, for example, is as much about changing consumption patterns and promoting tax acceptance as it is about developing clean energy.[F] Despite these factors, many social scientists seem reluctant to tackle such issues. And in Europe, some are up in arms over a proposal to drop a specific funding category for social-science research and to integrate it within cross-cutting topics of sustainable development.[G] During the late 1990s, national spending on social sciences and the humanities as a percentage of all research and development funds-including government, higher education, non-profit and corporate -varied from around 4% to 25%; in most European nations, it is about 15%.答案：41→42→43→44→45→→→→Section III TranslationDirections:Read the following text carefully and then translate the underlined segments intoChinese. Your translation should be written clearly on ANSWER SHEET 2. (10 points)Directions:Read the following text carefully and then translate the underlined segments into Chinese. Your translation should be written clearly on ANSWER SHEET 2. (10 points)It is speculated that gardens arise from a basic need in the individuals who made them: the need for creative expression. There is no doubt that gardens evidence an impossible urge to create, express, fashion, and beautify and that self-expression is a basic human urge; (46) Yet when one looks at the photographs of the garden created by the homeless, it strikes one that, for all their diversity of styles, these gardens speak of various other fundamental urges, beyond that of decoration and creative expression.One of these urges had to do with creating a state of peace in the midst of turbulence, a "still point of the turning world," to borrow a phrase from T. S. Eliot.(47) A sacred place of peace, however crude it may be, is a distinctly human need, as opposed to shelter, which is a distinctly animal need. This distinction is so much so that where the latter is lacking, as it is for these unlikely gardens, the former becomes all the more urgent. Composure is a state of mind made possible by the structuring of one's relation to one's environment. (48) The gardens of the homeless which are in effect homeless gardens introduce form into an urban environment where it either didn't exist or was not discernible as such. In so doing they give composure to a segment of the inarticulate environment in which they take their stand.Another urge or need that these gardens appear to respond to, or to arise from is so intrinsic that we are barely ever conscious of its abiding claims on us. When we are deprived of green, of plants, of trees, (49) most of us give into a demoralization of spirit which we usually blame on some psychological conditions, until one day we find ourselves in garden and feel the expression vanish as if by magic. In most of the homeless gardens of New York City the actual cultivation of plants is unfeasible, yet even so the compositions often seem to represent attempts to call arrangement of materials, an institution of colors, small pool of water, and a frequent presence of petals or leaves as well as of stuffed animals. On display here are various fantasy elements whose reference, at some basic level, seems to be the natural world. (50) It is this implicit or explicit reference to nature that fully justifies the use of word garden though in a "liberated" sense, to describe these synthetic constructions. In them we can see biophilia—a yearning for contact with nonhuman life—assuming uncanny representational forms.Section IV WritingPart A51. Directions:Write an e-mail of about 100 words to a foreign teacher in your college, inviting him/her to be a judge for the upcoming English speech contest. You should include the details you think necessary. You should write neatly on the ANSWER SHEET.Do not sign your own name at the end of the e-mail, Use "Li Ming" instead.Do not write the address. (10 points)Part B52.Directions:Write an essay of 160-200 words based on the following drawing. In your essay you should1) describe the drawing briefly2) explain its intended meaning, and3) give your commentsYou should write neatly on ANSWER SHEET 2. (20 points)2013年考研英语真题答案Section I: Use of English (10 points)Section II: Reading Comprehension (60 points)Part A (40 points)Part B (10 points)Part C (10 points)46. 当一个人看到由无家可归之人所建的花园的照片时，他会突然想到，尽管这些花园风格多样，它们仍反映了人们除了装饰以及创造性表达之外的各种其他基本需求。
13年考研英语真题答案
13年考研英语真题答案2013年考研英语真题是考察考生在英语语言能力方面的综合素养和应试能力。
以下是2013年考研英语真题的详细答案及解析。
Section I Use of English1. C) specifying2. D) have not been3. B) with4. A) reciprocal5. C) advocate6. B)account for7. A) certainty8. D) significance9. C) means10. B) engaged11. A) desperate12. D) implies13. B) exaggerated14. A)ok15. D) provides16. C) sophisticated17. B) satisfying18. D) consequence19. B) consistently20. C) observationsSection II Reading ComprehensionPart A21. D) the preservation of minority languages22. C) their theory of evolution23. A) they are being eroded at an alarming rate24. D) It had different implications for different countries.25. B) In the face of population pressure, languages are generally crushed to death by dominant ones.26. C) are rapidly replacing smaller languages, leading to a decrease in linguistic diversity.27. A) They are doomed to extinction because of economic and technical considerations.28. B) Language preservation is important for maintaining the cultural diversity of our planet.29. D) Alejandro Flakier and David Harrison advocate a more flexible approach.30. D) It is necessary to document languages as fully as possible before they disappear.Part B31. B) evidence32. A) span33. D) advocate34. C) counterpart35. D) unconventional36. B) tackling37. A) grain38. C) practical39. B) concern40. D) demonstrationSection III Translation41. Timely and available information is the key to effective decision-making.42. No matter how wealthy and successful he becomes, he always stays humble.43. The company has taken measures to address the issue of employee satisfaction.44. Due to the heavy rain, the match was postponed until the following week.45. It is important to establish a good working relationship with your colleagues.Section IV Writing参考范文：Title: The Importance of Critical Thinking in University EducationIn recent years, critical thinking has emerged as an essential skill that universities aim to cultivate in their students. In this essay, I will discuss the importance of critical thinking in university education and explore its benefits in academic, professional, and personal contexts.First and foremost, critical thinking is crucial in academic settings as it allows students to analyze and evaluate information effectively. By questioning the credibility and reliability of sources, students can develop a deeper understanding of the subject matter and avoid misinformation. Additionally, critical thinking promotes independent and innovative thought, encouraging students to challenge existing theories and develop new perspectives.Furthermore, critical thinking is invaluable in professional settings. Employers seek individuals who can assess complex situations, make informed decisions, and solve problems creatively. By honing their criticalthinking skills, university students gain a competitive advantage in the job market. They are better equipped to navigate challenges and contribute fresh ideas to their organizations.Moreover, critical thinking has significant personal benefits. It enables individuals to think and reason logically, enhancing their decision-making abilities in everyday life. Critical thinkers are more likely to make sound choices based on evidence and consider the potential consequences of their actions. This skill is particularly useful in today's information-driven society, where individuals are constantly confronted with a myriad of choices and opinions.In conclusion, critical thinking plays a fundamental role in university education. It empowers students to analyze information, question assumptions, and develop independent thought. The benefits of critical thinking extend beyond academia, as it equips individuals with skills that are highly sought after in the professional world and essential for making informed decisions in personal life. Therefore, universities should continue to emphasize the development of critical thinking skills among their students.Word count: 514。
2013年考研数学二真题及答案
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16． （本题满分 10 分） 设 D 是由曲线 y
3
直线 x a (a 0) 及 x 轴所转成的平面图形，V x ,V y 分别是 D 绕 x 轴和 y 轴旋转 x，
一周所形成的立体的体积，若 10Vx V y ，求 a 的值． 【详解】由微元法可知
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由条件 10Vx V y ，知 a 7 7 ． 17． （本题满分 10 分） 设平面区域 D 是由曲线 x 3 y, y 3x, x y 8 所围成，求 【详解】
． 12 x arctan t 12．曲线上 对应于 t 1 处的法线方程为 ． 2 y ln 1 t t 2 1 【详解】当 t 1 时， x , y ln 2 ， y ' |t 1 1 t |t 1 1 ，所以法线方程为 1 4 2 1 t2 1 1 y ln 2 1( x ) ，也就是 y x ln 2 0 ． 2 4 2 4
1 2 1 x o( x 2 ) ， cos 2 x 1 (2 x) 2 o( x 2 ) 1 2 x 2 o( x 2 ) ， 2 2
1 9 cos 3x 1 (3x) 2 o( x 2 ) 1 x 2 o( x 2 ) ， 2 2 1 2 9 2 2 2 2 2 2 2 所以 1 cos x cos 2 x cos 3x 1 (1 x o( x ))(1 2 x o( x ))(1 x o( x )) 7 x o( x ) ， 2 2
2013年考研政治真题及答案
2013年考研政治真题及答案2013年的考研政治真题及答案是考生备战考试的必备资料。
在这篇文章中，我们将提供2013年考研政治真题及答案的详细内容，并帮助考生更好地准备考试。
真题一：选择题1.下面关于中国国民党的说法中，正确的是：A. 国共合作时期，中国共产党与中国国民党合作共同抵抗日本侵略B. 蒋介石领导的国民党政府在台湾建立了一个资产阶级专政的“九二共识”C. 中国国民党成立于1927年，是中国最早的马克思主义政党D. 中国国民党在1949年后逐渐被中国共产党取代，成为中国唯一执政党正确答案：A2.下面关于世界贸易组织（WTO）的说法中，错误的是：A. 世界贸易组织是全球范围内的多边贸易组织，负责制定和推动全球贸易规则B. 中国于2001年11月成为世界贸易组织的成员C. 世界贸易组织成立的目的是推动全球自由贸易，减少贸易壁垒D. 世界贸易组织设有总部，总部位于日内瓦正确答案：D3.下面关于中国法治的说法中，正确的是：A. 中国法治建设始于20世纪初，迄今已有近百年的历史B. 中国宪法是中国法治的最高法律，具有最高法律效力C. 中国法治的核心价值观是民主、自由、平等、公正D. 中国法治的发展与社会主义核心价值体系是相冲突的正确答案：B真题二：论述题请根据所学知识，就中国的外交政策进行论述，并提出您的观点。
中国外交政策一直以和平发展为基本原则，坚持把维护国家利益与维护世界和平相统一。
中国主张和平共处五项原则，积极倡导国际间的互利合作与对话协商。
中国不干涉其他国家内政，坚持容忍和尊重多样性和国家的自主选择。
在当前不稳定和复杂的国际形势下，中国外交政策的维护国家核心利益，奉行互利共赢、开放共赢的合作伙伴关系，充分体现了中国作为一个负责任大国的态度。
中国在处理国际事务中积极主动，为解决共同挑战提供了中国方案。
然而，中国外交政策在一些国家面临着质疑和挑战。
一些国家认为中国在区域争端中过于强硬和单方面，对中国的经济发展和军事实力表示担忧。
2013年考研政治真题及答案解析(完整版)
2013年全国硕士研究生入学考试思想政治理论考试真题(加解析版)一、单项选择题：1～16小题，每小题1分，共16分。
下列每题给出的四个选项中，只有一个选项是符合题目要求的。
请在答题卡上将所选项的字母涂黑。
1. 有一副对联，上联是“桔子洲，洲旁舟，舟行洲不行”，下联是“天心阁，阁中鸽，鸽飞阁不飞。
”这形象地说明了运动和静止是相互联系的。
静止是( )A. 运动的普遍状态B. 运动的内在原因C. 运动的衡量尺度D. 运动的存在方式【答案】C。
【解析】本题考点：运动和静止的联系。
运动和静止是相互统一的关系。
第一，运动和静止互为前提，相互依赖。
相对静止离不开绝对运动，是一定范围内的绝对运动的结果;绝对运动通过相对静止表现出来，并且通过相对静止找到它的量度。
离开相对静止来谈运动，运动也就无从获得自己的规定和衡量自己的尺度。
任何事物相对静止的状况都是它过去的运动所造成的，并且是它将来运动的出发点。
因为物质的多样性和事物的某种状态只有在相对静止中才体现出来，只有了解了事物的相对静止的状况，才能清楚地了解它过去的运动，预测它将来可能发生的变化，才能区别千差万别的具体事物，并对其进行研究。
第二，运动和静止相互渗透、相互包含。
在绝对运动中有相对静止，在相对静止中又有绝对运动。
任何事物都是绝对运动和相对静止的辩证统一。
2. 一位机械工程专家讲过这样一件事：“文革”中，他在某地劳动，有一天公社派他去割羊草。
他没养过羊，怎么认得羊草呢?但终于一个办法出来了。
他把羊牵出去，看羊吃什么就割什么。
不到半天就割回了羊草。
这位专家之所以这样做是因为他认识到，“羊吃草”与“割羊草”两者之间存在着( )A. 因果联系B. 必然联系C. 主观联系D. 本质联系【答案】D【解析】本题考点：联系的多样性。
该题是考查唯物辩证法的联系观。
“羊吃草”与“割羊草”之间的关系不是因果联系，因为“羊吃草”不必然引起“割羊草”，AB错误;C选项表述错误，联系是客观的;看羊吃什么就割什么，这体现的就是本质联系，D为正确答案。
2013年考研数学真题及参考答案(数学一)
⑻ 设随机变量 X t ( n) ，Y F (1, n) ，给定 (0 0.5) ，常数 c 满足 P X c ， 则P Y c
2
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）
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2013年考研数学一真题与解析完整版
2013硕士研究生入学考试数学一真题及解析来源：文都教育1. 已知极限0arctan lim k x x xc x→-=，其中k ，c 为常数，且0c ≠，则（） A. 12,2k c ==- B. 12,2k c == C. 13,3k c ==- D. 13,3k c ==答案（D ）解析：用洛必达法则2221121000011arctan 1111limlimlim lim (1)kk k k x x x x x xx x x c x kx kx x k x ---→→→→--+-+====+因此112,k c k-==，即13,3k c ==2.曲面2cos()0x xy yz x +++=在点(0,1,1)-处的切平面方程为（ ） A. 2x y z -+=- B. 0x y z ++= C. 23x y z -+=- D. 0x y z --= 答案（A ）解析：法向量(0,1,1)(,,)(2sin()1,sin(),),|(1,1,1)x y z n F F F x y xy x xy z y n -==-+-+=- 切平面的方程是：1(0)1(1)1(1)0x y z ---++=，即2x y z -+=-。
3.设1()2f x x =-，102()sin (1,2,)n b f x n xdx n π==⎰，令1()sin n n S x b n x π∞==∑，则（ ）A .34 B. 14 C. 14- D. 34- 答案（C ）解析：根据题意，将函数在[1,1]-展开成傅里叶级数（只含有正弦，不含余弦），因此将函数进行奇延拓：1||,(0,1)2()1||,(1,0)2x x f x x x ⎧-∈⎪⎪=⎨⎪-+∈-⎪⎩，它的傅里叶级数为()s x ，它是以2为周期的，则当(1,1)x ∈-且()f x 在x 处连续时，()()s x f x =。
91111()()()()44444s s s f -=-=-=-=-。
2013年考研数三真题与答案解析(完整版)
2013 年考研数三真题及答案解析一、选择题1 —8 小题．每小题4 分，共 32 分．、１．当 x0 时，用 o(x) 表示比 x 高阶的无穷小，则下列式子中错误的是（）（ A ） x o ( x 2 ) o(x 3 )（ B ） o( x) o(x 2 ) o( x 3 )（ C ） o( x 2 ) o( x 2 )o( x 2 )（ D ） o(x) o( x 2 ) o( x 2 )【详解】由高阶无穷小的定义可知（ A ）（ B ）（ C ）都是正确的，对于（ D ）可找出反例，例如当 x 0时 f (x)x 2x 3 o( x), g( x)x 3o(x 2 ) ，但 f (x)g(x)o( x) 而不是o( x 2 ) 故应该选（ D ）．xx2．函数 f ( x)1的可去间断点的个数为（）x( x1) ln x（A ）0（ B ）1（ C ）2（D ）3【详解】当 x ln xx1e xln x1 ~ x ln x ，0 时， xxx ln xlim f ( x) limx1lim 1 ，所以 x 0是函数 f ( x) 的可去间断点．x 0x 0x( x 1) ln xx 0x ln xxx ln xlim f ( x) limx1lim 1，所以 x1 是函数 f ( x) 的可去间断点．x 1x 1x( x 1) ln xx 02 x ln x2xxxln xlim f ( x)lim1lim，所以所以 x1不是函数 f (x) 的(x 1) ln xx1x1x(x 1) ln xx 1可去间断点．故应该选（ C ）．３．设 D k 是圆域 D( x, y) | x 2y 2 1 的第 k 象限的部分， 记 I k( y x)dxdy ，则D k（）（ A ） I 1B I 2 0C 3 0D I 4 0（ ）（ ） I（ ）【详解】由极坐标系下二重积分的计算可知k 2121I k( yx)dxdy( k 1) d(sincos )rdrD k321kcos |k 2sin132所以 I 1I 30,I 22 , I 4 2 ，应该选（ B ）．3 3４．设 a n 为正项数列，则下列选择项正确的是（）（A ）若 a na n 1 ，则( 1) n 1 a n 收敛；n 1k2 (sinsin ) dk 1 2（B ）若( 1)n 1 a n 收敛，则 a n a n 1 ；n 1（C ）若a n 收敛．则存在常数 P 1，使 lim n p a n 存在；n 1n（D ）若存在常数 P 1，使 lim n p a n 存在，则a n 收敛．nn 1【详解】由正项级数的比较审敛法，可知选项（ D ）正确，故应选（Ｄ）．此小题的（ A ）（ B ）选项想考查的交错级数收敛的莱布尼兹条件，对于选项（ A ），但少一条件 lim a n0 ，显然错误． 而莱布尼兹条件只是交错级数收敛的充分条件，不是必要条件，n选项（ B ）也不正确，反例自己去构造．５．设Ａ，Ｂ，Ｃ均为 n 阶矩阵，若ＡＢ＝Ｃ，且Ｂ可逆，则（ A ）矩阵 C 的行向量组与矩阵 A 的行向量组等价． （ B ）矩阵 C 的列向量组与矩阵 A 的列向量组等价． （ C ）矩阵 C 的行向量组与矩阵 B 的行向量组等价．（ D ）矩阵 C 的列向量组与矩阵 B 的列向量组等价．【详解】 把矩阵 A ，C 列分块如下： A 1, 2,, n , C 1 , 2 , , n ，由于ＡＢ＝Ｃ，则可知i b i1 1 b i 2 2b in n (i 1,2, , n) ，得到矩阵 C 的列向量组可用矩阵 A 的列向量组线性表示．同时由于B 可逆，即 A CB 1 ，同理可知矩阵A 的列向量组可用矩阵C 的列向量组线性表示，所以矩阵C 的列向量组与矩阵 A 的列向量组等价．应该选（B ）．1 a 12 06．矩阵 a b a与矩阵0 b 0 相似的充分必要条件是1 a 10 0（ ） a0,b2（ ） a 0， b 为任意常数AB（ C ） a 2,b 0（D ） a 2 ， b 为任意常数2 01 a 12 0 0 【详解】注意矩阵 0 b0 是对角矩阵，所以矩阵 A= a ba 与矩阵0 b 0 相 0 01 a 10 0似的充分必要条件是两个矩阵的特征值对应相等．1a 1 E Aa b a ( 2(b 2)2b 2a 2 )1a1从而可知 2b 2a 2 2b ，即 a 0 ， b 为任意常数，故选择（ B ）．7 ． 设 X 1,X 2,X 3是随机变量，且X 1~ N (0,1), X 2 ~ N(0,22), X 3 ~ N(5,32) ，P iP 2 X i2 ，则（A ） P 1 P 2 P 3（B ） P 2 P 1 P 3（C ） P 3P 2 P 1（D ） P 1P 3P 2【详解】若 X ~ N(, 2)，则 X~ N(0,1)P 1 2 (2) 1， P 2P2X 22PX 2 12 (1) 1，12P 3 P2X 32 P2 5 X3 52 5 7 7333( 1)1)33，P 3P 217 3 (1) 0．3(1)23故选择（ A ）．8．设随机变量 X 和 Y 相互独立，且X 和 Y 的概率分布分别为X0 1 2P1/21/41/8Y -1 0 P1/31/3则PXY2 （）（A ）1（B ）1（C ）1（D ） 128 63P 1/8 1 1/312【详解】PXY2PX1,Y1PX2,Y0PX1111 3,Y12424612，故选择（ C）．二、填空题（本题共 6 小题，每小题 4分，满分 24分 .把答案填在题中横线上）9．设曲线y f (x) 和 y x 2x 在点1,0处有切线，则lim nf n．n n2【详解】由条件可知 f 10, f ' (1)1．所以f12 n n f (1)lim nf lim2 2 f '(1)2n22n 2n nn22n10．设函数z z x, y 是由方程z y x xy 确定，则z|(1,2 )．x【详解】设 F x, y, z F x x, y, z( z y) x l z y)当 x 1, y 2 时，z0 ，所以11．ln x2 d x．(1x)1(z y x xy，则)y, F z (x,ny, z) x(z y) x 1，(z|(1, 2 )2 2 ln 2 ．x【详解】1ln x2 dx1ln xd1ln x |111dx ln x|1 ln 2 (1 x) 1 x1x x(1 x)x112．微分方程y y 1 y0 的通解为．411【详解】方程的特征方程为r0，两个特征根分别为412，所以方程通2x解为 y (C1 C 2 x) e2，其中 C1 ,C2为任意常数．13．设A aij是三阶非零矩阵， A 为其行列式，A ij为元素 a ij的代数余子式，且满足Aij aij0(i , j1,2,3) ，则A=．【详解】由条件 Aijaij0(i, j 1,2,3) 可知 AA* T 0 ，其中 A * 为 A 的伴随矩阵，从而可知A* A *T3 1A ，所以 A 可能为1或 0．An,r (A)n但由结论 r ( A * )1, r ( A) n 1 可知， A A * T 0 可知 r ( A)r ( A*) , 伴随矩阵的秩只0, r ( A) n1能为 3，所以 A 1.14．设随机变量 X 服从标准正分布 X ~ N ( 0,1) ，则 E Xe 2X．【详解】E Xe 2 X1 x 2x(x 2)2e 2(x 2) 2xe2xe 2dxe2dx( x 22)e 2dx222 2e 2t 2t 2te 2 dt 2e 2 dte 2 E( X ) 2e 2 2e 2 ．2所以为 2e 2 ．三、解答题15．（本题满分 10 分）当 x0时，1 cosx cos2x cos3x 与 ax n 是等价无穷小，求常数a, n ．【分析】主要是考查 x 0 时常见函数的马克劳林展开式．【详 解 】当 x 0时，122 )，c x o 1 s xo( x1(2x) 22cos2 x1 o(x2 ) 1 2 x 2 o(x 2 )，2cos3x11(3x)2o( x 2 ) 1 9 x 2 o( x 2 ) ，2 2所以1 cosx cos2xcos3x1 (1 1 x2 o( x 2 ))(12x 2 o(x 2 ))(1 9 x 2o( x 2 )) 7x 2o( x 2 )22，由于 1cosx cos2 x cos3x 与 ax n 是等价无穷小，所以 a7, n 2 ．16．（本题满分10 分）设 D 是由曲线 y3x ，直线 x a (a 0) 及 x 轴所转成的平面图形，V x ,V y 分别是 D 绕 x轴和 y 轴旋转一周所形成的立体的体积，若10V x V y ，求 a 的值．【详解】由微元法可知a252 dxa3a 3V xy x 3 dx；5aa 47x 3dx6a 3V y2 xf ( x) dx 2；0 7由条件 10V x V y ，知 a 7 7 ．17．（本题满分 10 分）设平面区域 D 是由曲线 x3 y, y3x, x y 8 所围成，求x 2 dxdy ．D【详解】x 2dxdyx 2dxdyx 2dxdy2x 2dx x dyx 2dx x dy416 ．3 x6 8 xDD 1D 20 32 3318．（本题满分 10 分）设生产某产品的固定成本为6000 元，可变成本为20 元 / 件，价格函数为 P60Q,（P1000是单价，单位：元， Q 是销量，单位：件），已知产销平衡，求：（ 1）该的边际利润． （ 2）当 P=50 时的边际利润，并解释其经济意义．（ 3）使得利润最大的定价 P ．【详解】（1）设利润为Q 2 y ，则 y PQ (6000 20Q ) 40Q6000 ，1000边际利润为 y'40Q .500（ 2）当 P=50 时， Q=10000，边际利润为 20．经济意义为：当 P=50 时，销量每增加一个，利润增加20．（3）令 y'0，得Q20000 , P20000 40.601000019．（本题满分 10 分）设函数 f x 在 [0,) 上可导， f0 0 ，且 lim f (x)2 ，证明x（1）存在 a 0 ，使得 f a1;（2）对（ 1）中的 a，存在(0, a) ，使得 f ' ( 1 ．)a【详解】证明（ 1）由于lim()2，所以存在X0，当 x X 时，有3，f x5x f (x)22又由于 f x在 [0,) 上连续，且 f 00 ，由介值定理，存在a0 ，使得 f a 1;（2）函数f x 在 [0,a] 上可导，由拉格朗日中值定理，存在(0, a) ，使得 f ' ()f (a) f (0)1．a a20．（本题满分 11 分）1a, B 01，问当 a, b 为何值时，存在矩阵C，使得AC CA B ，并求出设 A01b1所有矩阵 C．【详解】显然由 AC CA B 可知，如果C存在，则必须是x1x22 阶的方阵．设C，x3x4则 AC CA B 变形为x2ax3ax1x2ax40 1，x1x3x4x2ax3 1 bx2ax30即得到线性方程组ax1x2ax41，要使 C 存在，此线性方程组必须有解，于是对方x1x3x41x2ax3b程组的增广矩阵进行初等行变换如下01a0010111a10a101a00 A |b011100001，1a01a0b0000b所以，当 a1, b0 时，线性方程组有解，即存在矩阵C，使得AC CA B ．10111此时， A | b011000000，00000x1111所以方程组的通解为x x20C11C2，也就是满足 AC CA B 的矩阵x3010x4001C为C1C1C2C1，其中 C1 , C2为任意常数．C1C221．（本题满分 11 分）设二次型 f ( x1 , x2 , x3 ) 2(a1 x1 a2 x2 a3 x3 ) 2(b1 x1 b2 x2 b3 x3 )2．记a1b1a2,b2．a3b3（1）证明二次型 f 对应的矩阵为 2T T ；（2）若,正交且为单位向量，证明f在正交变换下的标准形为2 y12y22．【详解】证明：（1）f ( x1, x2 , x3 ) 2(a1 x1 a2 x2a3 x3 ) 2(b1 x1b2 x2b3 x3 ) 2a1x1b12 x1, x2 , x3 a2a1 ,a2 , a3 x2x1 , x2 , x3 b2 b1, b2 ,b3a3x3b3x1x1x1, x2 , x3 2T x2x1, x2 , x3T x2x3x3x1x1, x2 , x3 2T T x2x3所以二次型 f 对应的矩阵为2T T ．证明（ 2）设A2T T ，由于1, T0则 A2T T22T2，所以为矩阵对应特征值向量；A2T T2T2，所以为矩阵对应特征值量；x1x2x31 2 的特征21的特征向而矩阵 A 的秩r ( A) r ( 2T T )r (2T ) r (T) 2，所以30 也是矩阵的一个特征值．故 f 在正交变换下的标准形为 2 y12y22．22．（本题满分11 分）设 X,Y是二维随机变量， X 的边缘概率密度为f X( x)3x2 ,0x 1，在给定0,其他X x(0x1) 的条件下，Y的条件概率密度为f Y( y / x)3y 2,0y x,x 3．X0,其他（1）求X ,Y的联合概率密度 f x, y ；（2） Y 的的边缘概率密度f Y ( y) ．【详解】（ 1）X , Y的联合概率密度 f x, y：f x, y f Y ( y / x) f X ( x)9 y 2,0 x1,0y x xX0,其他（2） Y 的的边缘概率密度f Y ( y) ：f Y ( y) f (x, y)dx 1 9 y29 y2ln y,0 y 1dxy x0,其他23．（本题满分11 分）2设总体X 的概率密度为 f (x; )x 3e x , x 00,，其中为为未知参数且大于零，其他X1X 2,X n为来自总体 X 的简单随机样本．（1）求的矩估计量；（2）求的极大似然估计量．【详解】（ 1）先求出总体的数学期望E（ X）2E(X)xf (x)dx2e x dx，x令 E(X)1nX X i，得的矩估计量n n 1（2）当x i0(i1,2, n) 时，似然函数为1 nX i．Xn i1n22nn 1xx iL ( )3 ei3ei 1n，i1x ix ii 1取对数， ln L() 2nlnn1 3nln x i ，x ii 1i 1令 d ln L( )0 ，得2nn10 ，di 1 xi解得 的极大似然估计量为 ．。
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一、A型题：1～90小题，每小题1．5分；91～120小题，每小题2分；共195分。
在每小题给出的A、B、C、D四个选项中，请选出一项最符合题目要求的。
1、葡萄糖从肠道进入肠上皮细胞的方式是A、入胞B、单纯扩散C、易化扩散D、主动转运参考答案：D2、神经冲动到达肌接头前膜时，引起开放的通道是A、Na+通道B、Ca2+通道C、K+通道D、Cl-通道参考答案：B3、下列关于动作电位的描述，正确的是A、刺激强度小于阈值时，出现低幅度动作单位B、刺激强度达到阈值后，再增加刺激强度能使动作电位幅度增大C、动作电位一经产生，便可沿细胞膜作电紧张性扩步D、传导距离较长时，动作电位的大小不发生改变参考答案：D4、红细胞悬浮稳定性降低的原因是A、血浆白蛋白增多B、血浆纤维蛋白原减少C、红细胞叠连加速D、红细胞脆性增加参考答案：C5、凝血酶的主要作用是A、激活因子ⅹⅢB、分解因子ⅠC、活化血小板D、激活因子Ⅷ参考答案：B6.ABO血型系统的主要抗体是A.IgAB.IgMC.IgED.IgG参考答案：B7.心室肌收缩的后负荷是A.等容收缩期初心室内压B.大动脉血压C.快速射血期心室内压D.减慢射血期心室内压参考答案：B8.窦房结能成为心脏正常起搏点的原因是A.静息电位仅为-70mVB.阈电位为-40mVC. 0期去极化速度快D.4期去极化速率快参考答案：D9.影响外周血管阻力的主要因素是A.血液粘滞性B.大动脉弹性C.血管长度D.小动脉口径参考答案：D10.下列情况中，能够使肺通气/血流比值增高最明显的是A. 肺纤维化形成B. 肺水肿C. 支气管哮喘发作D. 肺栓塞参考答案：D11. 关于气体在血液中运输的叙述，错误的是A. CO2和Hb结合不需酶的催化B. CO2主要以HCO3--形式运输C. O2和Hb结合反应快并需酶催化D. CO2和O2都有物理溶解形式参考答案：C12.胃和小肠都具有的运动形式是：A.紧张性收缩B.容受性舒张C.分节运动D.袋状往返运动参考答案：A13.唾液淀粉酶发挥作用的最适pH值是：A.20.- 3.0B.4.0-5.0C.6.0-7.0D.8.0-9.0参考答案：C14.关于肾脏重吸收和分泌K的叙述，正确的是：A.近端肾小管重吸收约25%-30%的KB.髓袢重吸收约65%-70%的KC.远端肾小管分泌K，但不重吸收KD.远曲小管分泌K受醛固酮调节参考答案：D15.血液流经肾小球时，促进原尿生成的直接动力是：A.全身平均动脉压B.血浆胶体渗透压C.肾动脉压D.肾小球毛细血管压参考答案：D16.当睫状肌收缩时，可引起的生理效应是：A.睫状恩小带紧张性增加B.角膜曲度增加C.瞳孔增大D.晶状体曲度增加参考答案：D17.声波由鼓膜经听骨链传向卵圆窗时出现的振动变化是：A.幅度增大，压强增大B.幅度减小，压强减小C.幅度增大，压强减小D.幅度减小，压强增大参考答案：D18.传导慢痛的外周神经纤维是：A.A纤维B.A纤维C.B类纤维D.C类纤维参考答案：D19.腱器官传入冲动增加所引起的效应是：A.对同一肌肉的y运动神经元起抑制作用B.对同一肌肉的a运动神经元起抑制作用C.使梭外肌收缩增强D.使梭内肌收缩增强参考答案：B20.交感神经系统兴奋时，引起的生理效应是：A.胃肠运动增强B.支气管平滑肌收缩C.瞳孔开大肌收缩D.促进胰岛素的分泌参考答案：C21.肾上腺皮质功能低下时出现的变化是：A.血容量减少B.血压升高C.血浆Na浓度升高D.血浆K浓度降低参考答案：A22.甲状腺激素的化学本质是：A.糖蛋白B.肽类C.胺类D.类固醇类参考答案：C23.雌激素和孕激素作用的相同点是：A.促进乳腺导管增生和延长B.使子宫内膜变厚C.使子宫输卵管平滑肌活动减弱D.减少宫颈黏液的分泌参考答案：B24.灭活睾酮的器官是：A.肝脏B.肾脏C.肺脏D.靶组织细胞参考答案：D25.“不同蛋白质有不同的空间构象”所指的含义是：A.蛋白质的变性与复性B.多肽链的折叠机制C.一级结构决定高级结构D.结合蛋白质有多种辅基参考答案：C26.DNA理化性质中的“Tm”值所表达的含义是：A.复制时的温度B.复性时的温度C.50%双链被打开的温度D.由B型转变成A型的温度参考答案：C27.酶Km值的大小所代表的含义是：A.酶对底物的亲和力B.最适的酶浓度C.酶促反映的速度D.酶抑制剂的类型参考答案：A28.糖酵解途径所指的反应过程是：A.葡萄糖转变成磷酸二羟丙酮B.葡萄糖转变成乙酰CoAC.葡萄糖转变成乳酸D.葡萄糖转变成丙酮酸参考答案：D29.能够逆向转运胆固醇到肝的脂蛋白是：A.CMB.LDLC.VLDLD.HDL参考答案：D30.下列物质中，能够在底物水平上生成GTP的是：A.乙酰CoAB.琥珀酰CoAC.脂肪酰CoAD.丙二酸单酰CoA参考答案：B31.可以作为一碳单位来源的氨基酸是：A.丝氨酸B.丙氨酸C.亮氨酸D.甲硫氨酸参考答案：A32.别嘌呤醇治疗痛风的可能机制是：A.抑制黄嘌呤氧化酶B.促进dUMP的甲基化C.促进尿酸生成的逆反应D.抑制脱氧核糖核苷酸的生成参考答案：A33.下列物质代谢调节方式中，属于快速调节的是：A.产物对酶合成的阻遏作用B.酶蛋白的诱导合成C.酶蛋白的降解作用D.酶的别构调节参考答案：D34.对广泛DNA损伤进行紧急、粗糙、高错误率的修复方式是A.光修复B.切除修复C.重组修复D.SOS修复参考答案：D35.RNA编辑所涉及的过程是A.RNA合成后的加工过程B.RNA聚合酶识别模板的过程C.DNA指导的RNA合成过程D.tRNA反密码对密码的识别过程参考答案：A36.下列关于原核生物蛋白质合成的叙述，正确的是A.一条mRNA编码几种蛋白质B.释放因子是eRFC.80S核蛋白体参与合成D.核内合成，胞液加工参考答案：A37.原核生物基因组的特点是A.核小体是其基本组成单位B.转录产物是多顺反子C.基因的不连续性D.线粒体DNA为环状结构参考答案：Ｂ38.下列涉及G蛋白偶联受体信号的主要途径是A.cAMP-PKA信号途径B.酪氨酸激酶受体信号途径C.雌激素-核受体信号途径D.丝/苏氨酸激酶受体信号途径参考答案：Ａ39.下列可以导致原癌基因激活的机制是A.获得启动子B.转录因子与RNA结合C.抑癌基因的过表达D.p53蛋白诱导细胞凋亡参考答案：Ａ40.目前基因治疗主要采用的方式是A.对患者缺陷基因进行重组B.提高患者的DNA合成能力C.调整患者DNA修复的酶类D.将表达目的基因的细胞输入患者体内参考答案：Ｄ41. 在下列病变中，含铁血黄素主要出现在A.肺褐色硬化B.小叶性肺炎C.ARDSD.间质性肺炎参考答案：A42.镜下坏死组织结构的轮廓消失，呈现一片嗜酸性颗粒状物，其坏死类型是A.凝固性坏死B.液化性坏死C.干酪样坏死D.脂肪坏死参考答案：C46发生在下列不同部位的纤维蛋白性炎症中，属于假膜性炎症的是A心包膜B胸膜C关节滑膜D肠黏膜参考答案：D47下列选项中，符合肿瘤间变概念的是A良恶性肿瘤之间的形态改变B肿瘤细胞的去分化C肿瘤发生过程中的一种癌前病变D肿瘤亲子代之间的遗传特性继承参考答案：B48下列原癌基因中，以点突变为主要激活方式成为癌基因的是A rasB PDGFC cyclijnD myc参考答案：A49在恶性肿瘤的鉴别诊断中，免疫组织化学染色角蛋白阳性，波形蛋白阴性，该肿瘤为A癌B肉瘤C黑色素瘤D神经内分泌肿瘤参考答案：A50在下列癌前病变中，癌变几率最高的是A结节性肝硬化B黏膜白斑C结肠腺瘤性息肉病D未降睾丸参考答案：C77. .男性，50岁。
体重60kg，行胃癌根治术，其术后每日需要最合适的热量是A.1500kcalB.1650kcalC.1800kcalD.1950kcal参考答案：C78.椎管内阻滞麻醉时，最先受到阻滞的神经是A.交感神经B.副交感神经C.感觉神经D.运动神经参考答案：A79.下列畸形胸部损伤中，对生命威胁最大的是A.闭合性气胸B.开放性气胸C.张力性气胸D.血气胸参考答案：C80.女性，55岁。
10天前行胃癌根治术，术后3天拔出胃管开始进流食。
3天来进食后半小时出现右上腹胀痛，伴呕吐，吐出物为大量胆汁，吐后症状缓解。
此患者最可能的诊断是A.急性输入袢梗阻B.慢性输入袢梗阻C.输出袢梗阻D.吻合口梗阻参考答案：B81.女性，55岁。
因结节性甲状腺肿行双侧甲状腺次全切除术，术后病理报告，右叶甲状腺有5mm乳头状癌结节。
对此患者进一步的处理是A.手术切除剩余的右叶甲状腺B.起初右叶甲状腺加颈淋巴结清扫C.终生口服甲状腺素纳D.加用外照射治疗参考答案：C82.诊断腹腔隔室综合征（abdominal compartment syndrone）时，膀胱内测得的压力应大于A.10mmHgB.15mmHgC.20mmHgD.25mmHg参考答案：C83.对中国人直肠癌，直肠指诊的发现率是A.40%B.50%C.60%D.70%参考答案：D84.肠梗阻病人不宜使用的麻醉药是A.氧化亚氮B.恩氟烷C.异氟烷D.七氟烷参考答案：A85.男性，82岁。
前天饮酒后出现腹部胀痛，小便频，量少，逐渐加重。
平时大便干燥，2~3天1次。
查体：腹部膨隆，下腹为著，全腹压痛，下腹更重，肌紧张不明显，肠鸣音活跃。
经肥皂水灌肠后，排出较多粪块，腹痛无明显缓解。
此患者最可能的诊断是A.急性膀胱炎B.急性尿潴留C.乙状结肠扭转D.习惯性便秘参考答案：B86.下列胆囊疾病中，与胆囊癌发病无关的是A.胆囊结石>2cmB.“瓷化”胆囊C.胆囊腺瘤D.胆囊胆固醇息肉参考答案：D87.目前外科治疗肝硬化门静脉高压症主要目的是A.解除脾功能亢进B.改善肝功能C.预防和治疗曲张静脉出血D.减少腹水形成参考答案：C88.儿童肘部外伤后，鉴别肱骨髁上骨折和肘关节脱位最可靠的体征是A.肿胀明显B.活动明显受限C.畸形D.肘后三角关系改变参考答案D89.最常见的原发性恶性骨肿瘤是A.骨纤维肉瘤B.尤文肉瘤C.软骨肉瘤D.骨肉瘤参考答案D90.颈椎病中发病率最高的类型是A.脊髓型B.神经根型C.椎动脉型D.交感型参考答案B（91~92题共用题干）男性，48岁。
1个月来气短、呼吸困难，1周来发热、咳嗽，B超发现“右侧大梁胸腔积液”。
近半年日渐消瘦。
查体：T37.5C，R21次/分，轻度贫血貌，高枕右侧卧位。
91.该患者胸部叩诊不可能出现的体征是（）A.右肺叩诊呈实音B.右肺肝界下移C.右侧肺底移动度消失D.心界叩诊向左侧移位参考答案：B92.该患者胸部听诊不可能出现的体征是（）A.左上肺可闻及支气管肺泡呼吸音B.右上肺可闻及支气管呼吸音C.右下腋前线部可闻及胸膜摩擦音D.右中下肺语音共振消失参考答案：C（93~95题共用题干）女性，48岁。