Attrition Defenses for a Peer-to-Peer Digital Preservation System
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2022年考研考博-考博英语-西北大学考试全真模拟易错、难点剖析AB卷(带答案)一.综合题(共15题)1.单选题Psychologists think of attitudes as being predisposition toward objects or events that determine the way people react to different stimuli.问题1选项A.prior inclinationsB.prescriptionsC.precautionsD.principal commitments【答案】A【解析】心理学家认为态度是对事物或事件的一种倾向,它决定了人们对不同刺激的反应方式。
predisposition意为“ 倾向”。
prior inclinations 倾向,爱好;prescriptions 医药处方;precautions预防措施,预警;principal commitments主要承诺。
选项A与之意思相近。
2.单选题The use of robots and automated machinery has eliminated certain ()factory jobs.问题1选项A.thrillingB.timidC.enticingD.tedious【答案】D【解析】thrilling 激动人心的;令人兴奋的;timid 胆小的,羞怯的;enticing 有吸引力的,诱人的;tedious 沉闷的,冗长乏味的。
句意:机器人和自动化机器的使用消除了某些单调乏味的工厂工作。
选项D符合句意。
3.翻译题大学之所以有理由存在,是因为它使老少两代人在富于想象力的学习中,保持了知识与生活热情之间的联系。
大学提供信息,但它是富于想象地提供信息。
至少,这是它应该为社会发挥的作用。
一所大学如果做不到这一点,就没有理由存在。
富于想象的思维可以营造出一种令人兴奋的氛围,而这种氛围又可以转化知识。
IntroductionThe concept of a pre-emptive strategy is deeply rooted in the realms of military tactics, business strategies, and international relations, often serving as a proactive measure to mitigate potential threats or exploit emerging opportunities. This approach involves taking decisive action before an adversary can do so, thereby gaining a strategic advantage. The application of this principle across various domains necessitates a thorough understanding of its dynamics and implications from multiple perspectives, especially when aiming for high-quality and high-standard decision-making.1. **Military Dimension**In the context of military strategy, a pre-emptive strike is a calculated offensive action undertaken to defeat an enemy's ability or intention to attack. This approach was notably employed in historical events such as the Six-Day War by Israel in 1967. From a high-quality, high-standard perspective, a successful pre-emptive military strategy requires meticulous intelligence gathering, advanced logistical planning, and precision execution. It must be backed by clear evidence of an imminent threat and align with ethical and legal frameworks to ensure it doesn't undermine global peace and stability.2. **Business and Economic Perspective**In the corporate world, a pre-emptive strategy might involve launching a new product, acquiring a competitor, or investing in innovative technology before rivals can. For instance, tech giants like Apple have often adopted a pre-emptive approach by continuously innovating and introducing products that disrupt markets before competitors can catch up. To execute such strategies at a high standard, businesses need to possess strong foresight, agile innovation capabilities, robust risk assessment, and a deep understanding of market dynamics. Quality here is measured by the effectiveness of the strategy in securing long-term competitive advantages and sustainable growth.3. **International Relations and Diplomacy**In international diplomacy, a pre-emptive strategy could mean diplomaticinitiatives to prevent conflicts, economic sanctions to deter aggressive behavior, or early negotiations to resolve disputes. The high standards lie in the ability to predict and defuse crises while maintaining respect for international law and norms. Quality in this realm means crafting smart policies that balance assertiveness with cooperation, promoting stability and mutual benefits over unilateral gains.4. **Environmental and Health Policy**Pre-emptive strategies also play a significant role in public health and environmental policy. Anticipatory measures such as vaccination campaigns before an epidemic spreads or preventative pollution control measures demonstrate this approach. Here, high quality and standards require scientific accuracy, swift response mechanisms, and equitable distribution of resources to protect the most vulnerable populations.5. **Legal and Regulatory Frameworks**In the legal field, pre-emptive legislation can anticipate future issues and set regulatory standards to prevent harm. For example, data privacy laws often pre-emptively address potential misuse of personal information. The challenge lies in striking the right balance between over-regulation and under-preparation, ensuring that the law is forward-thinking yet practical, and protective without stifling innovation – all hallmarks of a high-quality, high-standard legal framework.ConclusionIn summary, the adoption and execution of a pre-emptive strategy across different sectors require rigorous analysis, careful planning, and bold action. Its success is predicated on the ability to identify key indicators, forecast outcomes accurately, and act decisively within the confines of ethical, legal, and social norms. By adhering to these principles, organizations and governments can harness the power of a pre-emptive strategy to achieve high-quality and high-standard outcomes, whether it’s protecting national security, gaining market share, preserving global stability, safeguarding public health, orshaping regulatory landscapes. However, the complexity and unpredictability of human systems mean that even the best-laid plans may encounter unforeseen challenges; thus, continuous review, adaptation, and learning are crucial components of any effective pre-emptive strategy.While this overview has touched upon several dimensions, each context brings unique nuances that demand tailored approaches to meet the stringent criteria of high-quality, high-standard pre-emption. In essence, pre-emption is not merely about being first; it's about being right, responsible, and responsive in the face of uncertainty.。
九年级英语政治单选题60题1.Which international organization is dedicated to promoting world peace and security?A.UNESCOB.WHOC.UND.WTO答案:C。
本题考查国际组织的职能。
UN(联合国)致力于促进世界和平与安全。
UNESCO 联合国教科文组织)主要致力于教育、科学和文化领域。
WHO( 世界卫生组织)专注于全球卫生事务。
WTO 世界贸易组织)主要处理国际贸易问题。
2.The Belt and Road Initiative is a major example of ________.A.international cooperationB.domestic developmentC.regional conflictD.global isolation答案:A。
“一带一路”倡议是国际合作的重要范例。
B 选项国内发展不准确。
C 选项区域冲突与“一带一路”相悖。
D 选项全球孤立也不符合“一带一路”的理念。
3.Which of the following is NOT an international organization involved in economic cooperation?A.APECB.NATOC.OECDD.G20答案:B。
NATO( 北大西洋公约组织)主要是军事联盟,不是经济合作组织。
APEC( 亚太经合组织)、OECD( 经济合作与发展组织)、G20 二十国集团)都涉及经济合作。
4.The purpose of the World Trade Organization is to ________.A.regulate international tradeB.provide medical assistanceC.promote cultural exchangesD.ensure national security答案:A。
2009年江苏专转本(英语)真题试卷(题后含答案及解析)题型有:1. 2. V ocabulary and Structure 3. Cloze 4. 5. 6. WritingYoung Koreans are beginning to do it alone when it comes to finding a partner, though matchmaking is still the most common way for boys to meet girls. Professional matchmakers can make thousands of American dollars by introducing suitable marriage partners to each other, but partners also play a role in the process during which young Koreans meet. In Confucius Korea, when marriage is regarded as more of a business contract than a sacred thing, the scene of the first meeting is repeated hundreds of times a day in coffee shops in the main hotels around Seoul. The business of continuing the family lineage (血统) and keeping the bloodlines pure is often too important to be left to romance and chance encounters. Often, the girl will work out a system of secret signals with her mother, from which her parents ca. . tell if she is interested. For example, if the girl orders a coffee it might mean that she wants her parents to leave her alone with the boy, while a milk shows that she wants them to stay. Sometimes the matchmaking is not always so formal, with the introduction being made by friends. But whether through friends or families, there is hardly a Korean man or woman in the country who has not gone through this process—sometimes six or seven times.1.The word “matchmaking” in this passage means______.A.a very formal ritual(仪式)attended by boys and girlsB.introducing boys and girls to know each other for the purpose of marriage C.producing matches to make a fire or light a cigaretteD.arranging games between men and women正确答案:B解析:根据文章第二段可知matchmaker(媒人)赚钱的方式是“为别人介绍合适的结婚伴侣”,故matchmaking意思为“做媒”。
高二英语国际关系单选题40题1. The United States once imposed a series of economic sanctions on Iran mainly because of _______ issues.A. nuclearB. environmentalC. culturalD. educational答案:A。
解析:美国对伊朗实施经济制裁主要是围绕核问题。
nuclear表示核的,伊朗核问题是国际关系中的一个重要外交事件相关点。
而environmental是环境的,cultural是文化的,educational是教育的,这几个选项与美国对伊朗制裁的主要原因不符。
2. China's Belt and Road Initiative aims to promote economic cooperation and cultural exchanges among countries along the routes. One of the important aspects is infrastructure building. Which of the following is a typical infrastructure project?A. Building a hospitalB. Constructing a high - speed railwayC. Establishing a universityD. Opening a shopping mall答案:B。
解析:中国一带一路倡议旨在促进沿线国家的经济合作和文化交流,其中基础设施建设是重要方面。
constructing a high - speed railway(修建高速铁路)属于基础设施建设。
Building a hospital更多是医疗卫生方面,establishing a university是教育方面,opening a shopping mall是商业方面,均不符合基础设施建设这个典型的一带一路倡议中的重要内容。
九年级英语政治单选题60题1. There ____ a lot of students in the playground.A. isB. areC. haveD. has答案:B。
本题考查there be 句型的用法。
there be 句型表示“有”,be 动词的形式要根据后面的主语来确定。
students 是复数名词,所以要用are,A 选项is 用于单数名词,C 选项have 和 D 选项has 表示“拥有”,主语通常是人。
2. He often ____ his homework at home.A. forgetsB. forgetC. leftD. leaves答案:D。
本题考查动词的用法。
forget 表示“忘记”,通常忘记某事或某物,leave 有“遗留,落下”的意思。
often 表明是一般现在时,主语he 是第三人称单数,所以动词要用第三人称单数形式,A 选项forgets 不符合语境,C 选项left 是leave 的过去式,所以要用leaves。
3. The teacher asked us ____ quiet in the library.A. to keepB. keepingC. keepD. kept答案:A。
本题考查ask sb. to do sth.的用法,“要求某人做某事”,要用动词不定式,B 选项keeping 是动名词形式,C 选项keep 是动词原形,D 选项kept 是过去式,所以要用to keep。
4. I'm very hungry. I haven't eaten ____ for two days.A. somethingB. anythingC. nothingD. everything答案:B。
本题考查不定代词的用法。
something 通常用于肯定句,anything 用于否定句和疑问句,nothing 表示“没有东西”,everything 表示“一切”。
2023年考研英语一真题及答案详细解析2023年全国硕士硕士入学统一考试英语(一)试题及答案详细解析Section I Use of English :Directions: Read the following text. Choose the best word(s) for each numbered blank and mark A, B,C or D on the ANSWER SHEET. (10 points)Though not biologically related, friends are as “related” as fourth cousins, sharing about 1% of genes. That is _(1)_a study, published from the University of California and Yale University in the Proceedings of the National Academy of Sciences, has__(2)_.The study is a genome-wide analysis conducted _(3)__1,932 unique subjects which __(4)__pairs of unrelated friends and unrelated strangers. The same people were used in both_(5)_.While 1% may seem_(6)_,it is not so to a geneticist. As James Fowler, professor of medical genetics at UC San Diego, says, “Most people do not even _(7)_their fourth cousins but somehow manage to select as friends the people who_(8)_our kin.”The study_(9)_found that the genes for smell were something shared in friends but not genes for immunity .Why this similarity exists in smell genes is difficult to explain, for now,_(10)_,as the team suggests, it draws us to similar environments but there is more_(11)_it. There could be many mechanisms working together that _(12)_us in choosing genetically similar frien ds_(13)_”functional Kinship” of being friends with_(14)_!One of the remarkable findings of the study was the similar genes seem to beevolution_(15)_than other genes Studying this could help_(16)_why human evolution picked pace in the last 30,000 years, with social environment being a major_(17)_factor.The findings do not simply explain people’s_(18)_to befriend those of similar_(19)_backgrounds, say the researchers. Though all the subjects were drawn from a population of European extraction, care was taken to_(20)_that all subjects, friends and strangers, were taken from the same population.1. [A] when [B] why [C] how [D] what2. [A] defended [B] concluded [C] withdrawn [D] advised3. [A] for [B] with [C] on [D] by4. [A] compared [B] sought [C] separated [D] connected5. [A] tests [B] objects [C]samples [D] examples6. [A] insignificant [B] unexpected [C]unbelievable [D] incredible7. [A] visit [B] miss [C] seek [D] know8. [A] resemble [B] influence [C] favor [D] surpass9. [A] again [B] also [C] instead [D] thus10. [A] Meanwhile [B] Furthermore [C] Likewise [D] Perhaps11. [A] about [B] to [C]from [D]like12. [A] drive [B] observe [C] confuse [D]limit13. [A] according to [B] rather than [C] regardless of [D] along with14. [A] chances [B]responses [C]missions [D]benefits15. [A] later [B]slower [C] faster [D] earlier16. [A]forecast [B]remember [C]understand [D]express17. [A] unpredictable [B]contributory [C] controllable [D] disruptive18. [A] endeavor [B]decision [C]arrangement [D] tendency19. [A] political [B] religious [C] ethnic [D] economic20. [A] see [B] show [C] prove [D] tellSection 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. (40 points)Text 1King Juan Carlos of Spain once insisted “kings don’t abdicate, they dare in their sleep.” But embarrassing scandals and the popularity of the republican left in the recent Euro-elections have forced him to eat his words and stand down. So, does the Spanish crisis suggest that monarchy is seeing its last days? Does that mean the writing is on the wall for all European royals, with their magnificent uniforms and majestic lifestyle?The Spanish case provides arguments both for and against monarchy. When public opinion is particularly polarised, as it was following the end of the Franco regime, monarchs canrise above “mere” politics and “embody” a spirit of national unity.It is this apparent transcendence of politics that explains monarchs’ continuing popularity polarized. And also, the Middle East excepted, Europe is the most monarch-infested region in the world, with 10 kingdoms (not counting Vatican City and Andorra). But unlike their absolutist counterparts in the Gulf and Asia, most royal families have survived because they allow voters to avoid the difficult search for a non-controversial but respected public figure.Even so, kings and queens undoubtedly have a downside. Symbolic of national unity as they claim to be, their very history—and sometimes the way they behave today –embodies outdated and indefensible privileges and inequalities. At a time when Thomas Piketty and other economists are warning of rising inequality and the increasing power of inherited wealth, it is bizarre that wealthy aristocratic families should still be the symbolic heart of modern democratic states.The most successful monarchies strive to abandon or hide their old aristocratic ways. Princes and princesses have day-jobs and ride bicycles, not horses (or helicopters). Even so, these are wealthy families who party with the international 1%, and media intrusiveness makes it increasingly difficult to maintain the right image.While Euro pe’s monarchies will no doubt be smart enough to survive for some time to come, it is the British royals who have most to fear from the Spanish example.It is only the Queen who has preserved the monarchy’s reputation with her rather ordinary (if well-heeled) granny style. The danger will come with Charles, who has both anexpensive taste of lifestyle and a pretty hierarchical view of the world. He has failed to understand that monarchies have largely survived because they provide a service – as non-controversial and non-political heads of state. Charles ought to know that as English history shows, it is kings, not republicans, who are the monarchy’s worst enemies.21. According to the first two Paragraphs, King Juan Carlos of Spain[A] used turn enjoy high public support[B] was unpopular among European royals[C] cased his relationship with his rivals[D]ended his reign in embarrassment22. Monarchs are kept as heads of state in Europe mostly[A] owing to their undoubted and respectable status[B] to achieve a balance between tradition and reality[C] to give voter more public figures to look up to[D]due to their everlasting political embodiment23. Which of the following is shown to be odd, according to Paragraph 4?[A] Ari stocrats’ excessive reliance on inherited wealth[B] The role of the nobility in modern democracies[C] The simple lifestyle of the aristocratic families[D]The nobility’s adherence to their privileges24. The British royals “have most to fear” because Charles[A] takes a rough line on political issues[B] fails to change his lifestyle as advised[C] takes republicans as his potential allies[D] fails to adapt himself to his future role25. Which of the following is the best title of the text?[A] Carlos, Glory and Disgrace Combined[B] Charles, Anxious to Succeed to the Throne[C] Carlos, a Lesson for All European Monarchs[D]Charles, Slow to React to the Coming ThreatsText 2Just how much does the Constitution protect your digital data? The Supreme Court will now consider whether police can search the contents of a mobile phone without a warrant if the phone is on or around a person during an arrest.California has asked the justices to refrain from a sweeping ruling particularly one that upsets the old assumption that authorities may search through the possessions of suspects at the time of their arrest. It is hard, the state argues, for judges to assess the implications of new and rapidly changing technologies.The court would be recklessly modest if it followed California’s advice. Enough of the implications are discernable, even obvious, so that the justices can and should provide updated guidelines to police, lawyers and defendants.They should start by discard ing California’s lame argument that exploring the contents of a smart phone — a vast storehouse of digital information — is similar to, say, rifling through a suspect’s purse. The court has ruled that police don’t violate the Fourth Amendment when they sif t through the wallet or pocketbook of an arrestee without a warrant. But exploring one’s smart phone is more like entering his or her home. A smart phone may contain an arrestee’s reading history, financial history, medical history and comprehensive records of recent correspondence. The development of “cloud computing,” meanwhile, has made that exploration so much the easier.Americans should take steps to protect their digital privacy. But keeping sensitive information on these devices is increasingly a requirement of normal life. Citizens still have a right to expect private documents to remain private and protected by the Constitution’s prohibition on unreasonable searches.As so often is the case, stating that principle doesn’t ease the challenge of line-drawing. In many cases, it would not be overly onerous for authorities to obtain a warrant to search through phone contents. They could still invalidate Fourth Amendment protections when facing severe, urgent circumstances, and they could take reasonable measures to ensure that phone data are not erased or altered while a warrant is pending. The court, though, may want to allow room for police to cite situations where they are entitled to more freedom.But the justices should not swallow California’s argument whole. New, disruptive technology sometimes demands novel applications of the Constitution’s protections. Orin Kerr, a law professor, compares the explosion and accessibility of digital information in the 21st centurywith the establishment of automobile use as a virtual necessity of life in the 20th: The justices had to specify novel rules for the new personal domain of the passenger car then; they must sort out how the Fourth Amendment applies to digital information now.26. The Supreme Court will work out whether, during an arrest, it is legitimate to[A] prevent suspects from deleting their phone contents.[B] search for suspects’ mobile phones without a warrant.[C] check suspects’ phone contents without being authorized.[D]prohibit suspects from using their mobile phones.27. The author’s attitude toward California’s argument is one of[A] disapproval.[B] indifference.[C] tolerance.[D]cautiousness.28. The author believes that exploring one’s phone contents is comparable to[A] getting into one’s residence.[B] handling one’s historical records.[C] scanning one’s correspondences.[D] going through one’s wallet.29. In Paragraph 5 and 6, the author shows his concern that[A] principles are hard to be clearly expressed.[B] the court is giving police less room for action.[C] citizens’ privacy is not effectively protected.[D] phones are used to store sensitive information.30. Orin Kerr’s comparison is quoted to indicate that[A] the Constitution should be implemented flexibly.[B] new technology requires reinterpretation of the Constitution.[C]California’s argument violates principles of the Constitution.[D]principles of the Constitution should never be alteredText 3The journal Science is adding an extra round of statistical checks to its peer-review process, editor-in-chief Marcia McNutt announced today. The policy follows similar efforts from other journals, after widespread concern that basic mistakes in data analysis are contributing to the irreproducibility of many published research findings.“Readers must have confidence in the conclusions published in our journal,” writes McNutt in an editorial. Working with the American Statistical Association, the journal has appointed seven experts to a statistics board of reviewing editors(SBoRE). Manuscript will be flagged up for additional scrutiny by the journal’s internal editors, or by its existing Board of Reviewing Editors or by outside peer reviewers. The SBoRE panel will then find external statisticians to review these manuscripts.Asked whether any particular papers had impelled the change, McNutt said: “Thecreation of the ‘statistics board’ was motivated by concerns broadly with the application of statistics and data ana lysis in scientific research and is part of Science’s overall drive to increase reproducibility in the research we publish.”Giovanni Parmigiani, a biostatistician at the Harvard School of Public Health, a member of the SBoRE group. He says he expects th e board to “play primarily an advisory role.” He agreed to join because he “found the foresight behind the establishment of the SBoRE to be novel, unique and likely to have a lasting impact. This impact will not only be through the publications in Science itself, but hopefully through a larger group of publishing places that may want to model their approach after Science.”John Ioannidis, a physician who studies research methodology, says that the policy is “a most welcome step forward” and “long overdue.” “Most journals are weak in statistical review, and this damages the quality of what they publish. I think that, for the majority of scientific papers nowadays, statistical review is more essential than expert review,” he says. But he noted that biomedical journals such as Annals of Internal Medicine, the Journal of the American Medical Association and The Lancet pay strong attention to statistical review.Professional scientists are expected to know how to analyze data, but statistical errors are alarmingly common in published research, according to David Vaux, a cell biologist. Researchers should improve their standards, he wrote in 2023, but journals should also take a tougher line, “engaging reviewers who are statistically literate and editors who can verify the process”. Vaux says that Science’s idea to pass some papers to statisticians “has some merit, but aweakness is that it relies on the board of reviewing editors to identify ‘the papers that need scrutiny’ in the first place”.31. It can be learned from Paragraph 1 that[A] Science intends to simplify their peer-review process.[B] journals are strengthening their statistical checks.[C] few journals are blamed for mistakes in data analysis.[D] lack of data analysis is common in research projects.32. The phrase “flagged up” (Para. 2) is the closest in meaning to[A] found.[B] marked.[C] revised.[D] stored.33. Giovanni Parmigiani believes that the establishment of the SBoRE may[A] pose a threat to all its peers.[B] meet with strong opposition.[C] increase Science’s circulation.[D]set an example for other journals.34. David Vaux holds that what Science is doing now[A] adds to researchers’ workload.[B] diminishes the role of reviewers.[C] has room for further improvement.[D]is to fail in the foreseeable future35. Which of the following is the best title of the text?[A] Science Joins Push to Screen Statistics in Papers.[B] Professional Statisticians Deserve More Respect[C] Data Analysis Finds Its Way onto Editors’ Desks[D] Statisticians Are Coming Back with ScienceText 4Two years ago, Rupert Murdoch’s daughter ,Elisabeth ,spoke of the “unsettling dearth of integrity across so many of our institutions” Integrity had collapsed, she argued, because of a collective acceptance that the only “sorting mechanism ”in society should be profit and the market .But “it’s us ,human beings ,we the people who create the society we want ,not profit ”.Driving her point home, she continued: “It’s increasingly apparent that the absence of purpose, of a moral language within government, media or business could become one of the most dangerous foals for capitalism and freedom.” This same absence of moral purpose was wounding companies such as News International ,shield thought ,making it more likely that it would lose its way as it had with widespread illegal telephone hacking .As the hacking trial concludes –finding guilty ones-editor of the News of the World, Andy Coulson, for conspiring to hack phones ,and finding his predecessor, Rebekah Brooks, innocent of the same charge –the winder issue of dearth of integrity still standstill, Journalists areknown to have hacked the phones of up to 5,500 people .This is hacking on an industrial scale ,as was acknowledged by Glenn Mulcaire, the man hired by the News of the World in 2023 to be the point person for phone hacking. Others await trial. This long story still unfolds.In many respects, the dearth of moral purpose frames not only the fact of such widespread phone hacking but the terms on which the trial took place .One of the astonishing revelations was how little Rebekah Brooks knew of what went on in her newsroom, wow little she thought to ask and the fact that she never inquired wow the stories arrived. The core of her successful defence was that she knew nothing.In today’s world, title has become normal that well—paid executives should not be accountable for what happens in the organizations that they run perhaps we should not be so surprised. For a generation, the collective doctrine has been that the sorting mechanism of society should be profit. The words that have mattered are efficiency, flexibility, shareholder value, business–friendly, wealth generation, sales, impact and, in newspapers, circulation. Words degraded to the margin have been justice fairness, tolerance, proportionality and accountability.The purpose of editing the News of the World was not to promote reader understanding to be fair in what was written or to betray any common humanity. It was to ruin lives in the quest for circulation and impact. Ms Brooks may or may not have had suspicions about how her journalists got their stories, but she asked no questions, gave no instructions—nor received traceable, recorded answers.36. According to the first two paragraphs, Elisabeth was upset by[A] the consequences of the current sorting mechanism[B] companies’ financial loss due to immoral practices.[C] governmental ineffectiveness on moral issues.[D]the wide misuse of integrity among institutions.37. It can be inferred from Paragraph 3 that[A] Glem Mulcaire may deny phone hacking as a crime[B] more journalists may be found guilty of phone hacking.[C] Andy Coulson should be held innocent of the charge.[D] phone hacking will be accepted on certain occasions.38. The author believes the Rebekah Books’s deference[A] revealed a cunning personality[B] centered on trivial issues[C] was hardly convincing[D] was part of a conspiracy39. The author holds that the current collective doctrine shows[A] generally distorted values[B] unfair wealth distribution[C] a marginalized lifestyle[D] a rigid moral cote40. Which of the following is suggested in the last paragraph?[A] The quality of writing is of primary importance.[B] Common humanity is central news reporting.[C] Moral awareness matters in exciting a newspaper.[D] Journalists need stricter industrial regulations.Part BDirections:In the following text, some sentences have been removed. For Questions 41-45, choose the most suitable one from the fist A-G to fit into each of the numbered blanks. Mark your answers on ANSWER SHEET. (10 points)How does your reading proceed? Clearly you try to comprehend, in the sense of identifying meanings for individual words and working out relationships between them, drawing on your explicit knowledge of English grammar (41) ______you begin to infer a context for the text, for instance, by making decisions about what kind of speech event is involved: who is making the utterance, to whom, when and where.The ways of reading indicated here are without doubt kinds of of comprehension. But they show comprehension to consist not just passive assimilation but of active engagement inference and problem-solving. You infer information you feel the writer has invited you to grasp by presenting you with specific evidence and cues (42) _______Conceived in this way, comprehension will not follow exactly the same track for each reader. What is in question is not the retrieval of an absolute, fixed or “true” meaning that can beread off and clocked for accuracy, or some timeless relation of the text to the world. (43) _______ Such background material inevitably reflects who we are, (44) _______This doesn’t, however, make interpretation merely relative or even pointless. Precisely because readers from different historical periods, places and social experiences produce different but overlapping readings of the same words on the page-including for texts that engage with fundamental human concerns-debates about texts can play an important role in social discussion of beliefs and values.How we read a given text also depends to some extent on our particular interest in reading it. (45)_______such dimensions of read suggest-as others introduced later in the book will also do-that we bring an implicit (often unacknowledged) agenda to any act of reading. It doesn’t then necessarily follow that one kind of reading is fuller, more advanced or more worthwhile than another. Ideally, different kinds of reading inform each other, and act as useful reference points for and counterbalances to one another. Together, they make up the reading component of your overall literacy or relationship to your surrounding textual environment.[A] Are we studying that text and trying to respond in a way that fulfils the requirement of a given course? Reading it simply for pleasure? Skimming it for information? Ways of reading on a train or in bed are likely to differ considerably from reading in a seminar room.[B] Factors such as the place and period in which we are reading, our gender ethnicity, age and social class will encourage us towards certain interpretation but at the same time obscure or even close off others.[C] If you are unfamiliar with words or idioms, you guess at their meaning, using cluespresented in the contest. On the assumption that they will become relevant later, you make a mental note of discourse entities as well as possible links between them.[D]In effect, you try to reconstruct the likely meanings or effects that any given sentence, image or reference might have had: These might be the ones the author intended.[E]You make further inferences, for instance, about how the test may be significant to you, or about its validity—inferences that form the basis of a personal response for which the author will inevitably be far less responsible.[F]In plays,novels and narrative poems, characters speak as constructs created by the author, no t necessarily as mouthpieces for the author’s own thoughts.[G]Rather, we ascribe meanings to test on the basis of interaction between what we might call textual and contextual material: between kinds of organization or patterning we perceive in a text’s formal structures (so especially its language structures) and various kinds of background, social knowledge, belief and attitude that we bring to the text.Section III TranslationDirections:Read the following text carefully and then translate the underlined segments into Chinese. Your translation should be written clearly on ANSWER SHEET. (10 points) Within the span of a hundred years, in the seventeenth and early eighteenth centuries, a tide of emigration—one of the great folk wanderings of history—swept from Europe to America.46) This movement, driven by powerful and diverse motivations, built a nation out of a wilderness and, by its nature, shaped the character and destiny of an uncharted continent.47) The United States is the product of two principal forces-the immigration of European peoples with their varied ideas, customs, and national characteristics and the impact of a new country which modified these traits. Of necessity, colonial America was a projection of Europe. Across the Atlantic came successive groups of Englishmen, Frenchmen, Germans, Scots, Irishmen, Dutchmen, Swedes, and many others who attempted to transplant their habits and traditions to the new world.48) But, the force of geographic conditions peculiar to America, the interplay of the varied national groups upon one another, and the sheer difficulty of maintaining old-world ways in a raw, new continent caused significant changes. These changes were gradual and at first scarcely visible. But the result was a new social pattern which, although it resembled European society in many ways, had a character that was distinctly American.49) The first shiploads of immigrants bound for the territory which is now the United States crossed the Atlantic more than a hundred years after the 15th- and 16th-century explorations of North America. In the meantime, thriving Spanish colonies had been established in Mexico, the West Indies, and South America. These travelers to North America came in small, unmercifully overcrowded craft. During their six- to twelve-week voyage, they subsisted on barely enough food allotted to them. Many of the ship were lost in storms, many passengers died of disease, and infants rarely survived the journey. Sometimes storms blew the vessels far off their course, andoften calm brought unbearably long delay.“To the anxious travelers the sight of the American sh ore brought almost inexpressible relief.” said one recorder of events, “The air at twelve leagues’ distance smelt as sweet as a new-blown garden.” The colonists’ first glimpse of the new land was a sight of dense woods. 50) The virgin forest with its richness and variety of trees was a veritable real treasure-house which extended from Maine all the way down to Georgia. Here was abundant fuel and lumber. Here was the raw material of houses and furniture, ships and potash, dyes and naval stores.Section IV WritingPart A51. Directions:You are going to host a club reading session. Write an email of about 100 words recommending a book to the club members.You should state reasons for your recommendation.You should write neatly on the ANSWER SHEET.Do not sign your own name at the end of the letter. 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. (20 points)时代旳聚会参照答案及详细解析I cloze1. [A] when [B] why [C] how [D] what【答案】[D] what【解析】该题考察旳是语法知识。
高一英语跨文化交际策略单选题40题1.In some Western countries, nodding the head means “yes”, while in some Asian countries, shaking the head means “yes”. In India, people often shake their heads to show ___.A.agreementB.disagreementC.uncertaintyD.impatience答案:A。
在印度,人们摇头通常表示同意。
选项B“disagreement”是不同意;选项C“uncertainty”是不确定;选项D“impatience”是不耐烦。
2.In the United States, a thumbs-up sign usually means ___.A.approvalB.requestC.warningD.disapproval答案:A。
在美国,竖起大拇指通常表示赞成、认可。
选项B“request”是请求;选项C“warning”是警告;选项D“disapproval”是不赞成。
3.In Japan, bowing is a common form of greeting. A deep bow usually indicates ___.A.respectB.familiarityC.indifferenceD.disrespect答案:A。
在日本,鞠躬是常见的问候方式。
深深鞠躬通常表示尊敬。
选项B“familiarity”是熟悉;选项C“indifference”是冷漠;选项D“disrespect”是不尊敬。
4.In some Middle Eastern countries, pointing with the index finger is considered ___.A.politeB.rudeC.friendlyD.formal答案:B。
2024年高二英语学科全球合作研究的合作机制构建分析单选题30题1.International cooperation is crucial for addressing global challenges. The ______ of different countries is essential.A.effortsanizationsC.cooperationsD.initiatives答案:B。
“国际合作对于应对全球挑战至关重要。
不同国家的组织是必不可少的。
”A 选项“efforts”努力;C 选项“cooperations”合作,此处与前文重复;D 选项“initiatives”倡议。
根据语境,这里强调不同国家的组织,所以选B。
2.Global cooperation requires strong ______ among nations.A.associationsB.partnershipsC.connectionsD.relationships答案:B。
“全球合作需要国家之间强大的伙伴关系。
”A 选项“associations”协会;C 选项“connections”联系;D 选项“relationships”关系,而伙伴关系更能体现全球合作的需求,所以选B。
3.The success of global cooperation depends on effective ______.A.coordinationsB.arrangementsanizationsD.plans答案:C。
“全球合作的成功取决于有效的组织。
”A 选项“coordinations”协调;B 选项“arrangements”安排;D 选项“plans”计划。
这里强调组织的重要性,所以选C。
4.In global cooperation, ______ play an important role in promoting common development.A.institutionspaniesC.factoriesD.schools答案:A。
擅长作战样式评价英文Evaluating Combat Styles: A Technical Analysis.In the realm of military strategy, the evaluation of combat styles is crucial for achieving success on the battlefield. Different styles of warfare have their unique strengths and weaknesses, and understanding these nuances is essential for making informed decisions. This article aims to provide a technical analysis of various combat styles, exploring their advantages, disadvantages, and applications in modern warfare.1. Blitzkrieg (Lightning War)。
Blitzkrieg, or "lightning war," was a tactic pioneered by Germany in the early 20th century. It emphasized rapid, surprise attacks using mobile armored units and motorized infantry to quickly overwhelm enemy defenses. Blitzkrieg's main strengths lie in its speed and surprise, which can shatter enemy morale and collapse resistance quickly.However, this style is highly dependent on technology and logistics, and it can be vulnerable to enemy counterattacks if the initial assault fails to achieve its objectives.2. Guerilla Warfare.Guerilla warfare involves small, mobile units attacking enemy supply lines, rear areas, and other vulnerabletargets to disrupt and wear down the enemy. This style excels in prolonged conflicts where conventional forces may be outnumbered or outgunned. Guerilla warfare requires significant intelligence gathering, local support, and adaptability, but it can be highly effective in wearing down enemy morale and resources. However, it also has the risk of escalating into full-scale conflict if the enemy responds with disproportionate force.3. Attrition Warfare.Attrition warfare involves the gradual wearing down of the enemy through sustained combat, often over an extended period. This style aims to exhaust the enemy's resources,manpower, and morale through continuous attacks and defense. Attrition warfare is effective when both sides are evenly matched in terms of technology and resources, and it can be used to grind down enemy resistance over time. However, it can also lead to staggering losses on both sides and isoften slow and costly.4. Maneuver Warfare.Maneuver warfare focuses on using speed, mobility, and deception to outmaneuver the enemy. This style emphasizesthe use of indirect attacks, feints, and surprise maneuvers to create advantageous positions and gain the initiative. Maneuver warfare requires highly trained and mobile forces that can adapt quickly to changing situations. It is effective against enemy forces that are slower or less mobile, but it can also be risky if the enemy anticipates and counters the maneuvers.5. Information Warfare.Information warfare, or cyberwarfare, involves the useof technology to disrupt, degrade, or destroy enemy information systems. This style aims to gain a strategic advantage by manipulating information, disrupting enemy communications, and targeting critical infrastructure. Information warfare requires highly skilled operators and advanced technology, but it can be devastatingly effective in modern conflicts where information is critical to success. However, it also raises significant ethical and legal concerns about the use of force against civilian targets.In conclusion, the evaluation of combat styles is crucial for military planners and commanders. Understanding the strengths and weaknesses of different styles allows for more informed decisions about strategy and tactics. While no single style is perfect, a combination of different approaches can be effective in achieving military objectives. The key is to adapt and innovate, continuously learning from past conflicts and applying that knowledge to future battles.。
2024年6月大学英语六级考试真题和答案(第3套)Part I Writing (30 minutes)Directions: For this part, you are allowed 30 minutes to write an essay that begins with the sentence “Nowadays, cultivating independent learning ability is becoming increasingly crucial for personal development.” You can make comments, cite examples or use your personal experiences to develop your essay. You should write at least 150 words but no more than 200 words.You should copy the sentence given in quotes at the beginning of your essay.Part Ⅱ Listening Comprehension (30 minutes)Section ADirections:In this section, you will hear two long conversations. At the end of each conversation, you will hear four questions. Both the conversation and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D). Then mark the corresponding letter on Answer Sheet 1 with a single line through the centre.Questions 1 to 4 are based on the conversation you have just heard.1. A) Read numerous comments users put online.B) Blended all his food without using a machine.C) Searched for the state-of-the-art models of blenders.D) Did thorough research on the price of kitchen appliances.2. A) Eating any blended food.B) Buying a blender herself.C) Using machines to do her cooking.D) Making soups and juices for herself.3. A) Cooking every meal creatively in the kitchen.B) Paying due attention to his personal hygiene.C) Eating breakfast punctually every morning.D) Making his own fresh fruit juice regularly.4. A) One-tenth of it is sugar.B) It looks healthy and attractive.C) One’s fancy may be tickled by it.D) It contains an assortment of nutrients.Questions 5 to 8 are based on the conversation you have just heard.5. A) How he has made himself popular as the mayor of Berkton.B) How the residents will turn Berkton into a tourist attraction.C) How charming he himself considers the village of Berkton to be.D) How he has led people of Berkton to change the village radically.6. A) It was developed only to a limited extent.B) It was totally isolated as a sleepy village.C) It was relatively unknown to the outside.D) It was endowed with rare natural resources.7. A) The people in Berkton were in a harmonious atmosphere.B) The majority of residents lived in harmony with their neighbors.C) The majority of residents enjoyed cosy housing conditions.D) All the houses in Berkton looked aesthetically similar.8. A) They have helped boost the local economy.B) They have made the residents unusually proud.C) They have contributed considerably to its popularity.D) They have brought happiness to everyone in the village.Section BDirections: In this section, you will hear two passages. At the end of each passage, you will hear three or four questions. Both the passage and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A),B),C) and D). Then mark the corresponding letter on Answer Sheet 1 with a single line through the centre.Questions 9 to 11 are based on the passage you have just heard.9. A) They have created the smallest remote-controlled walking robot in the world.B) They are going to publish their research findings in the journal Science Robotics.C) They are the first to build a robot that can bend, crawl, walk, turn and even jump.D) They are engaged in research on a remote-controlled robot which uses special power.10. A) It changes its shape by complex hardware.B) It is operated by a special type of tiny motor.C) It moves from one place to another by memory.D) It is powered by the elastic property of its body.11. A) Replace humans in exploratory tasks.B) Perform tasks in tightly confined spaces.C) Explore the structure of clogged arteries.D) Assist surgeons in highly complex surgery.Questions 12 to 15 are based on the passage you have just heard.12. A) She threw up in the bathroom.B) She slept during the entire ride.C) She dozed off for a few minutes.D) She boasted of her marathon race.13. A) They are mostly immune to cognitive impairment.B) They can sleep soundly during a rough ride at sea.C) They are genetically determined to need less sleep.D) They constitute about 13 percent of the population.14. A) Whether there is a way to reach elite status.B) Whether it is possible to modify one’s genes.C) Whether having a baby impacts one’s passion.D) Whether one can train themselves to sleep less.15. A) It is in fact quite possible to nurture a passion for sleep.B) Babies can severely disrupt their parents’ sleep patterns.C) Being forced to rise early differs from being an early bird.D) New parents are forced to jump out of bed at the crack of dawn.Section CDirections: In this section, you will hear three recordings of lectures or talks followed by three or four questions. The recordings will be played only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D). Then mark the corresponding letter on Answer Sheet 1 with a single line through the centre.Questions 16 to 18 are based on the recording you have just heard. 16. A) We have poor awareness of how many controversial issues are being debated.B) No one knows better than yourself what you are thinking about at the moment.C) No one can change your opinions more than those who speak in a convincing tone.D) We are likely to underestimate how much we can be swayed by a convincing article.17. A) Their belief about physical punishment changed.B) Their memory pushed them toward a current belief.C) The memory of their initial belief came back to them.D) Their experiences of physical punishment haunted them.18. A) They apparently have little to do with moderate beliefs.B) They don’t reflect the changes of view on physical punishment.C) They may not apply to changes to extreme or deeply held beliefs.D) They are unlikely to alter people’s position without more evidence.Questions 19 to 21 are based on the recording you have just heard.19. A) American moms have been increasingly inclined to live alone.B) The American population has been on the rise in the past 25 years.C) American motherhood has actually been on the decline.D) The fertility rates in America have in fact been falling sharply.20. A) More new mothers tend to take greater care of their children.B) More new mothers are economically able to raise children.C) A larger proportion of women take pride in their children.D) A larger proportion of women really enjoy motherhood.21. A) The meaning of motherhood has changed considerably.B) More and more mothers go shopping to treat themselves.C) More mothers have adult children celebrating the holiday.D) The number of American mothers has been growing steadily.Questions 22 to 25 are based on the recording you have just heard.22. A) Add to indoor toxic pollutants.B) Absorb poisonous chemicals.C) Beautify the home environment.D) Soak up surrounding moisture.23. A) NASA did experiments in sealed containers resembling thesuper-insulated offices of 1970s.B) It was based on experiments under conditions unlike those in most homes or offices.C) NASA conducted tests in outer space whose environment is different from ours.D) It drew its conclusion without any contrastive data from other experiments.24. A) Natural ventilation proves much more efficient for cleaning the air than house plants.B) House plants disperse chemical compounds more quickly with people moving around.C) Natural ventilation turns out to be most effective with doors and windows wide open.D) House plants in a normal environment rarely have any adverse impact on the air.25. A) The root cause for misinterpretations of scientific findings.B) The difficulty in understanding what’s actually happening.C) The steps to be taken in arriving at any conclusion with certainty.D) The necessity of continually re-examining and challenging findings.Part III Reading Comprehension (40 minutes)Section ADirections: In this section, there is a passage with ten blanks. You are required to select one word for each blank from a list of choices given in a word bank following the passage. Read the passage through carefully before making your choices. Each choice in the bank is identified by a letter. Please mark the corresponding letter for each item on Answer Sheet 2with a single line through the centre. You may not use any of the words in the bank more than once.A rainbow is a multi-colored, arc-shaped phenomenon that can appearin the sky. The colors of a rainbow are produced by the reflectionand____26____of light through water droplets (小滴) present in the atmosphere. An observer may____27____a rainbow to be located either near or far away, but this phenomenon is not actually located at any specific spot. Instead, the appearance of a rainbow depends entirely upon the position of the observer in____28____to the direction of light. In essence, a rainbow is an____29____illusion.Rainbows present a____30____made up of seven colors in a specific order. In fact, school children in many English-speaking countries are taught to remember the name “Roy G. Biv” as an aid for remembering the colors of a rainbow and their order. “Roy G. Biv”____31____for: red, orange, yellow, green, blue, indigo, and violet. The outer edge of the rainbow arc is red, while the inner edge is violet.A rainbow is formed when light (generally sunlight) passes through water droplets____32____in the atmosphere. The light waves change direction as they pass through the water droplets, resulting in two processes: reflection and refraction (折射). When light reflects off a water droplet, it simply____33____back in the opposite direction from where it____34____. When light refracts, it takes a different direction. Some individuals refer to refracted light as “bent light waves.” A rainbow is formed because white light enters the water droplet, where it bends in several different directions. When these bent light waves reach the other side of the water droplet, they reflect back out of the droplet instead of____35____passing through the water. Since the white light is separated inside of the water, the refracted light appears as separate colors to the human eye.A) bouncesB) completelyC) dispersionD) eccentricE) hangingF) opticalG) originatesH) perceiveI) permeatesJ) ponderK) precedingL) recklesslyM) relationN) spectrumO) standsSection BDirections: In this section, you are going to read a passage with tenstatements attached to it. Each statement contains information given in one of the paragraphs. Identify the paragraph from which the information is derived. You may choose a paragraph more than once. Each paragraph is marked with a letter. Answer the questions by marking the corresponding letter on Answer Sheet 2.Blame your worthless workdays on meeting recovery syndromeA) Phyllis Hartman knows what it’s like to make one’s way through the depths of office meeting hell. Managers at one of her former human resources jobs arranged so many meetings that attendees would fall asleep at the table or intentionally arrive late. With hours of her day blocked up with unnecessary meetings, she was often forced to make up her work during overtime. “I was actually working more hours than I probably would have needed to get the work done,” says Hartman, who is founder and president of PGHR Consulting in Pittsburgh, Pennsylvania.B) She isn’t alone in her frustration. Between 11 million and 55 million meetings are held each day in the United States, costing most organisations between 7% and 15% of their personnel budgets. Every week, employees spend about six hours in meetings, while the average manager meets for a staggering 23 hours.C) And though experts agree that traditional meetings are essential for making certain decisions and developing strategy, some employees view them as one of the most unnecessary parts of the workday. The result is not only hundreds of billions of wasted dollars, but an annoyance of what organisational psychologists call “meeting recovery syndrome (MRS)”: time spent cooling off and regaining focus after a useless meeting. If you run to the office kitchen to get some relief with colleagues after a frustrating meeting,you’re likely experiencing meeting recovery syndrome.D) Meeting recovery syndrome is a concept that should be familiar to almost anyone who has held a formal job. It isn’t ground-breaking to say workers feel fatigued after a meeting, but only in recent decades have scientists deemed the condition worthy of further investigation. With its links to organisational efficiency and employee wellbeing, MRS has attracted the attention of psychologists aware of the need to understand its precise causes and cures.E) Today, in so far as researchers can hypothesise, MRS is most easily understood as a slow renewal of finite mental and physical resources. When an employee sits through an ineffective meeting their brain power is essentially being drained away. Meetings drain vitality if they last too long, fail to engage employees or turn into one-sided lectures. The conservation of resources theory, originally proposed in 1989 by Dr. Stevan Hobfoll, states that psychological stress occurs when a person’s resources are threatened or lost. When resources are low, a person will shift into defence to conserve their remaining supply. In the case ofoffice meetings, where some of employees’ most valuable resources are their focus, alertness and motivation, this can mean an abrupt halt in productivity as they take time to recover.F) As humans, when we transition from one task to another on the job —say from sitting in a meeting to doing normal work—it takes an effortful cognitive switch. We must detach ourselves from the previous task and expend significant mental energy to move on. If we are already drained to dangerous levels, then making the mental switch to the next thing is extra tough. It’s common to see people cyber-loafing after a frustrating meeting, going and getting coffee, interrupting a colleague and telling them about the meeting, and so on.G) Each person’s ability to recover from horrible meetings is different. Some can bounce back quickly, while others carry their fatigue until the end of the workday. Yet while no formal MRS studies are currently underway, one can loosely speculate on the length of an average employee’s lag time. Switching tasks in a non-MRS condition takes about 10 to 15 minutes. With MRS, it may take as long as 45 minutes on average. It’s even worse when a worker has several meetings that are separated by 30 minutes. “Not enough time to transition in a non-MRS situation to get anything done, and in an MRS situation, not quite enough time to recover for the next meeting,” says researcher Joseph Allen. “Then, add the compounding of back-to-back bad meetings and we may have an epidemic on our hands.”H) In an effort to combat the side effects of MRS, Allen, along with researcher Joseph Mroz and colleagues at the University of Nebraska-Omaha, published a study detailing the best ways to avoid common traps, including a concise checklist of do’s and don’ts applicable to any workplace. Drawing from around 200 papers to compile their comprehensive list, Mroz and his team may now hold a remedy to the largely undefined problem of MRS.I) Mroz says a good place to start is asking ourselves if our meetings are even necessary in the first place. If all that’s on the agenda is a quick catch-up, or some non-urgent information sharing, it may better suit the group to send around an email instead. “The second thing I would always recommend is keep the meeting as small as possible,” says Mroz. “If they don’t actually have some kind of immediate input, then they can follow up later. They don’t need to be sitting in this hour-long meeting.” Less time in meetings would ultimately lead to more employee engagement in the meetings they do attend, which experts agree is a proven remedy for MRS.J) Employees also feel taxed when they are invited together to meetings that don’t inspire participation, says Cliff Scott, professor of organisational science. It takes precious time for them to vent their emotions, complain and try to regain focus after a pointless meeting—one of the main traps of MRS. Over time as employees find themselves tied up in more and more unnecessary meetings—and thus dealing with increasing lag times from MRS—the waste of workday hours can feel insulting.K) Despite the relative scarcity of research behind the subject, Hartman has taught herself many of the same tricks suggested in Mroz’s study, and has come a long way since her days of being stuck with unnecessary meetings. The people she invites to meetings today include not just the essential employees, but also representatives from every department that might have a stake in the issue at hand. Managers like her, who seek input even from non-experts to shape their decisions, can find greater support and cooperation from their workforce, she says.L) If an organisation were to apply all 22 suggestions from Mroz and Allen’s findings, the most noticeable difference would be a stark decrease in the total number of meetings on the schedule, Mroz says. Lesstime in meetings would ultimately lead to increased productivity,which is the ultimate objective of convening a meeting. While none of the counter-MRS ideas have been tested empirically yet, Allen says one trick with promise is for employees to identify things that quickly change their mood from negative to positive. As simple as it sounds, finding a personal happy place, going there and then coming straight back to work might be key to facilitating recovery.M) Leaders should see also themselves as “stewards of everyone else’s valuable time”, adds Steven Rogelberg, author of The Surprising Science of Meetings. Having the skills to foresee potential traps and treat employees’ endurance with care allows leaders to provide effective short-term deterrents to MRS.N) Most important, however, is for organisations to awaken to the concept of meetings being flexible, says Allen. By reshaping the way they prioritise employees’ time, companies can eliminate the very sources of MRS in their tracks.36. Although employees are said to be fatigued by meetings, the condition has not been considered worthy of further research until recently. 37. Mroz and his team compiled a list of what to do and what not to do to remedy the problem of MRS.38. Companies can get rid of the root cause of MRS if they give priority to workers’ time.39. If workers are exhausted to a dangerous degree, it is extremely hard for them to transition to the next task.40. Employees in America spend a lot of time attending meetings while the number of hours managers meet is several times more.41. Phyllis Hartman has learned by herself many of the ways Mroz suggested in his study and made remarkable success in freeing herself fromunnecessary meetings.42. When meetings continue too long or don’t engage employees, they deplete vitality.43. When the time of meetings is reduced, employees will be more engaged in the meetings they do participate in.44. Some employees consider meetings one of the most dispensable parts of the workday.45. According to Mroz, if all his suggestions were applied, a very obvious change would be a steep decrease in the number of meetings scheduled.Section CDirections:There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A), B), C) and D). You should decide on the best choice and mark the corresponding letter on Answer Sheet 2 with a single line through the centre.Passage OneQuestions 46 to 50 are based on the following passage.Sarcasm and jazz have something surprisingly in common: You know them when you hear them. Sarcasm is mostly understood through tone of voice, which is used to portray the opposite of the literal words. For example, when someone says, “Well, that’s exactly what I need right now,” their tone can tell you it’s not what they need at all.Most frequently, sarcasm highlights an irritation or is, quite simply, mean.If you want to be happier and improve your relationships, cut out sarcasm. Why? Because sarcasm is actually hostility disguised as humor.Despite smiling outwardly, many people who receive sarcastic comments feel put down and often think the sarcastic person is rude, or contemptible. Indeed, it’s not surprising that the origin of the word sarcasm derives from the Greek word “sarkazein” which literally means “to tear or strip the flesh off.” Hence, it’s no wonder that sarcasm is often preceded by the word “cutting” and that it hurts.What’s more, since actions strongly determine thoughts and feelings, when a person consistently acts sarcastically it may only serve to heighten their underlying hostility and insecurity. After all, when you come right down to it, sarcasm can be used as a subtle form of bullying —and most bullies are angry, insecure, or cowardly.Alternatively, when a person stops voicing negative comments, especially sarcastic ones, they may soon start to feel happier and more self-confident. Also, other people in their life benefit even more because they no longer have to hear the emotionally hurtful language of sarcasm.Now, I’m not saying all sarcasm is bad. It may just be better usedsparingly—like a potent spice in cooking. Too much of the spice, and the dish will be overwhelmed by it. Similarly, an occasional dash of sarcastic wit can spice up a chat and add an element of humor to it. But a big or steady serving of sarcasm will overwhelm the emotional flavor of any conversation and can taste very bitter to its recipient.So, tone down the sarcasm and work on clever wit instead, which is usually without any hostility and thus more appreciated by those you’re communicating with. In essence, sarcasm is easy while true, harmless wit takes talent.Thus, the main difference between wit and sarcasm is that, as already stated, sarcasm is often hostility disguised as humor. It can be intended to hurt and is often bitter and biting. Witty statements are usually in response to someone’s unhelpful remarks or behaviors, and the intent is to untangle and clarify the issue by emphasizing its absurdities. Sarcastic statements are expressed in a cutting manner; witty remarks are delivered with undisguised and harmless humor.46. Why does the author say sarcasm and jazz have something surprisingly in common?A) Both are recognized when heard.B) Both have exactly the same tone.C) Both mean the opposite of what they appear to.D) Both have hidden in them an evident irritation.47. How do many people feel when they hear sarcastic comments?A) They feel hostile towards the sarcastic person.B) They feel belittled and disrespected.C) They feel a strong urge to retaliate.D) They feel incapable of disguising their irritation.48. What happens when a person consistently acts sarcastically?A) They feel their dignity greatly heightened.B) They feel increasingly insecure and hostile.C) They endure hostility under the disguise of humor.D) They taste bitterness even in pleasant interactions.49. What does the author say about people quitting sarcastic comments?A) It makes others happier and more self-confident.B) It restrains them from being irritating and bullying.C) It benefits not only themselves but also those around them.D) It shields them from negative comments and outright hostility.50. What is the chief difference between a speaker’s wit and sarcasm?A) Their clarity.B) Their appreciation.C) Their emphasis.D) Their intention.Passage TwoQuestions 51 to 55 are based on the following passage.Variability is crucially important for learning new skills. Consider learning how to serve in tennis. Should you always practise serving from the exactly same location on the court, aiming at the same spot? Although practising in more variable conditions will be slower at first, it will likely make you a better tennis player in the end. This is because variability leads to better generalisation of what is learned.This principle is found in many domains, including speech perception and learning categories. For instance, infants will struggle to learn the category “dog” if they are only exposed to Chihuahuas, instead of many different kinds of dogs.“There are over ten different names for this basic principle,” says Limor Raviv, the senior investigator of a recent study. “Learning from less variable input is often fast, but may fail to generalise to new stimuli.”To identify key patterns and understand the underlying principles of variability effects, Raviv and her colleagues reviewed over 150 studies on variability and generalisation across fields, including computer science, linguistics, categorisation, visual perception and formal education.The researchers discovered that, across studies, the term variability can refer to at least four different kinds of variability, such as set size and scheduling. “These four kinds of variability have never been directly compared—which means that we currently don’t know which is most effective for learning,” says Raviv.The impact of variability depends on whether it is relevant to the task or not. But according to the ‘Mr. Miyagi principle’, practising seemingly unrelated skills may actually benefit learning of other skills.But why does variability impact learning and generalisation? One theory is that more variable input can highlight which aspects of a task are relevant and which are not.Another theory is that greater variability leads to broader generalisations. This is because variability will represent the real world better, including atypical (非典型的) examples.A third reason has to do with the way memory works: when training is variable, learners are forced to actively reconstruct their memories.“Understanding the impact of variability is important for literally every aspect of our daily life. Beyond affecting the way we learn language, motor skills, and categories, it even has an impact on our social lives,”explains Raviv. “For example, face recognition is affected by whether people grew up in a small community or in a larger community. Exposure to fewer faces during childhood is associated with diminished face memory.”“We hope this work will spark people’ s curiosity and generate morework on the topic,” concludes Raviv.“Our paper raises a lot of open questions. Can we find similar effects of variability beyond the brain, for instance, in the immune system?”51. What does the passage say about infants learning the category “dog”if they are exposed to Chihuahuas only?A) They will encounter some degree of difficulty.B) They will try to categorise other objects first.C) They will prefer Chihuahuas to other dog species.D) They will imagine Chihuahuas in various conditions.52. What does Raviv say about the four different kinds of variability?A) Which of them is most relevant to the task at hand is to be confirmed.B) Why they have an impact on learning is far from being understood.C) Why they have never been directly compared remains a mystery.D) Which of them is most conducive to learning is yet to be identified.53. How does one of the theories explain the importance of variability for learning new skills?A) Learners regard variable training as typical of what happens in the real world.B) Learners receiving variable training are compelled to reorganise their memories.C) Learners pay attention to the relevant aspects of a task and ignore those irrelevant.D) Learners focus on related skills instead of wasting time and effort on unrelated ones.54. What does the passage say about face recognition?A) People growing up in a small community may find it easy to remember familiar faces.B) Face recognition has a significant impact on literally every aspect of our social lives.C) People growing up in a large community can readily recognise any individual faces.D) The size of the community people grow up in impacts their face recognition ability.55. What does Raviv hope to do with their research work?A) Highlight which aspects of a task are relevant and which are not to learning a skill.B) Use the principle of variability in teaching seemingly unrelated skills in education.C) Arouse people’s interest in variability and stimulate more research on the topic.D) Apply the principle of variability to such fields of study as the immune system.。
2022年考研考博-考博英语-西北大学考试全真模拟易错、难点剖析AB卷(带答案)一.综合题(共15题)1.单选题These are signs that the presidency will attempt to put environmental issues on high its ().问题1选项A.legislationB.trendC.mainstreamD.agenda【答案】D【解析】legislation 立法,法律;trend 趋势,倾向;mainstream 主流;agenda 议程,日程表。
句意:这些迹象表明,总统将试图把环境问题提上议程。
选项D符合句意。
2.单选题然而, 研究人员在报告中提醒说, 相对于患更严重的疾病的危险来说, 这些益处简直微不足道。
问题1选项A.Researchers in the study, however, cautioned that such benefits don't outweigh the risk of more serious ailments.B.However, researchers reminded in the report that such benefits are nothing compared with the risk of more serious ailments.C.However, researchers cautioned in their report that such benefits don't indolence a lot comparing to the risk of more serious ailments.【答案】A【解析】“提醒”在本句中用remind比较口语化,caution更为正式,因为是在报告中进行提醒,因此caution更为恰当;后面包含一个比较,用outweigh言简意賅,最为恰当。
2015年5月9日前程百利托福独立写作机经预测大范围目录考题第一次出现时间:2008-12-12NA (6)考题第一次出现时间:2008-8-6NA (7)考题第一次出现时间:2008-10-12NA (9)考题第一次出现时间:2008-10-31NA (10)考题第一次出现时间:2008-3-1NA (10)考题第一次出现时间:2008-3-29NA (10)考题第一次出现时间:2008-5-30NA (10)考题第一次出现时间:2008-8-3CN (11)考题第一次出现时间:2008-8-2NA (11)考题第一次出现时间:2008-9-27NA (11)考题第一次出现时间:2012-4-20NA (13)考题第一次出现时间:2008-10-25NA (13)考题第一次出现时间:2008-1-5CN (13)考题第一次出现时间:2008-3-14NA (13)考题第一次出现时间:2008-5-16NA (15)考题第一次出现时间:2012-4-14NA (17)考题第一次出现时间:2012-7-22CN (19)考题第一次出现时间:2013-2-2NA (21)考题第一次出现时间:2013-2-23NA (23)考题第一次出现时间:2013-3-2NA (25)考题第一次出现时间:2013-4-6NA (26)考题第一次出现时间:2013-4-12NA (28)考题第一次出现时间:2013-5-17NA (29)考题第一次出现时间:2013-5-18CN (30)考题第一次出现时间:2013-6-22CN (30)考题第一次出现时间:2013-9-13NA (32)考题第一次出现时间:2013-9-14CN (33)考题第一次出现时间:2013-9-27NA (33)考题第一次出现时间:2013-10-5CN (34)考题第一次出现时间:2013-10-20CN (34)考题第一次出现时间:2013-12-7CN (34)考题第一次出现时间:2012-5-26NA (34)考题第一次出现时间:2008-9-21NA (34)考题第一次出现时间:2008-2-1NA (34)考题第一次出现时间:2013-1-12NA (35)考题第一次出现时间:2012-7-28NA (35)考题第一次出现时间:2012-8-25NA (35)考题第一次出现时间:2012-8-25CN (35)考题第一次出现时间:2012-10-19CN (35)考题第一次出现时间:2012-11-16NA (36)考题第一次出现时间:2013-5-31NA (38)考题第一次出现时间:2013-6-8NA (39)考题第一次出现时间:2013-7-13NA (41)考题第一次出现时间:2013-9-28CN (41)考题第一次出现时间:2013-10-19CN (41)考题第一次出现时间:2012-11-17NA (41)考题第一次出现时间:2012-10-6NA (42)考题第一次出现时间:2012-7-8NA (42)考题第一次出现时间:2012-8-17NA (42)考题第一次出现时间:2012-1-14CN (42)考题第一次出现时间:2008-12-12NA题目:Do you agree or disagree with the following statement:Physical exercises are much more important to the elderly people than to the young people.考题出现历次时间:2008-12-12NA,2010-1-30NA,2010-1-31CN,2011-7-31CN答题思路:Two-way BrainstormingAgree1Elderly people need to do exercise to maintain health2Education is more important to kids3Admittedly,young kids need to do exercise to strengthen their bodyDisagree1Little kids are more vulnerable to diseases such as flu and doing physical exercises can equip kids with stronger body to fight against bacteria2.For kids,physical exercise can facilitate the body in some aspect like gathering information.Young people today are less dependent on their parents3.Doing exercise can enable elderly people to strengthen their body and extend their life.口语答案:In the park built around neighborhoods,it is common that a bunch of people,ranging from3years old to80years old,are busy with doing exercise Some of the elderly people may argue that doing exercise is more important for people of their age.However,from my perspective, I think doing exercises are much more important to elderly people.First of all,little kids are more vulnerable to diseases such as flus and doing physical exercises can equip kids with stronger told me that he used to be very weak However,after participating in some clubs like swimming club.His muscle got strengthened and compared with other kids,he seldom caught cold.In addition,for kids,physical exercise can facilitate the growth of body Contrary-to kids.Elder people can no longer grow taller.So,doing physical exercises make more sense for kids in this aspect For instance.My nephew used to be a fat boy by playing basketball every day;he grew into a big tall guy.Admittedly,doing exercise can enable elderly people to strengthen their body and extend their life. However,from the facts above,it is clearly that doing exercises bring more benefits to kids than elderly people.All in all,I disagree with the idea that physical exercises are much more important to elderly people than young people.考题第一次出现时间:2008-8-6NA题目:Do you agree or disagree with the following statement:Most business people are motivatedby the desire for money.考题出现历次时间:2008-8-6NA,2008-8-16NA,2010-6-26CN,2011-10-27CN答题思路:Introduction(disagree)•Most business organizations exist to make a profit,but it would be wrong to say that business people are motivated purely by the desire for greater wealth.Main Body1Many successful companies have their social responsibilities.•They raise funds for children's charities.•They actively defend women's rights.,•A significant portion of profit goes to great causes.Main Body2An established enterprise has environmental?•They abide by environmental protection laws.•The emphasis is on sustainable Safeguarding environment and human health is the top priority. Main Body3Visionary business leaders are interested in innovation.•They invest enormously in scientific research.•Advanced technology is their life's passion.•They aim to create a better world in the futureConclusion•Apart from their ambitions for money,business people can be motivated by social and environmental responsibilities as well as their enthusiasm for creativity.口语答案:It is true that most business organizations exist to make aprofit,but it would be wrong to say that business people are motivated purely by the desire for greater wealth.To start with,apart from desires for profits,many successful companies have their social responsibilities.For example,they raise fund for children,charities;they actively defend women’s rights and a significant portion of portion of profit goes to great causes.Beyond all doubt,money is not the only essential factor that is considered by the business people.Secondly,an established enterprise is always committed to the environmental obligations.Most clearly,they never fail to abide by environmental protection laws because they consider it necessary to put the emphasis on sustainable development instead immediate interests.In their mind,it is always the top priority to safeguard the environment and human health.Therefore,it would be an exaggeration to say the business people only desire for money. Lastly,there are always quite a few business leaders who are interested in innovation.With great enthusiasm,they invest enormously in scientific research,aiming to create a better world.For most of them,all their life’s passion is devoted to the pursuit of advanced technology.Thus,it is unfair to say they are mercenary.To sum up,anyone who thinks most business people are only motivated by the desire for money is sorely mistaken.Apart from their ambitions for money,business people can be motivated by social and environmental responsibilities as well as their enthusiasm for creativity.考题第一次出现时间:2008-10-12NA题目:Do you agree or disagree with the following statement:In order to achieve success,we must be more like others than be different from others.考题出现历次时间:2008-10-12NA,2010-2-7CN,2013-10-12CN考题第一次出现时间:2008-10-31NA题目:Some people think to watch a movie in a cinema(theater)is better,but others think at home is better,which one do you prefer?考题出现历次时间:2008-10-31NA,2009-10-18CN,2013-6-8CN考题第一次出现时间:2008-3-1NA题目:Do you agree or disagree with the following statement:To solve the present and future problems,it is necessary to understand the past.考题出现历次时间:2008-3-1NA,2010-3-6CN,2011-9-18CN考题第一次出现时间:2008-3-29NA题目:Do you agree or disagree with the following statement:It is more important to have rules about the types of clothing that people wear at work and at school.考题出现历次时间:2008-3-29NA,2009-11-14CN,2013-8-24CN考题第一次出现时间:2008-5-30NA题目:Do you agree or disagree with the following statement:People today are not as friendlyas people were in the past.考题出现历次时间:2008-5-30NA,2009-9-20CN,2013-7-14CN考题第一次出现时间:2008-8-3CN题目:Do you agree or disagree with the following statement?Twenty years from now on,people will have more leisure time than they do now.考题出现历次时间:2008-8-3CN,2009-6-7CN,2011-5-29CN考题第一次出现时间:2008-8-2NA题目:Do you agree or disagree with the following statement?It is easier to succeed nowadays than in the past.考题出现历次时间:2008-8-2NA,2009-10-10CN,2011-5-29CN考题第一次出现时间:2008-9-27NA题目:Do you agree or disagree with the following statement:Printed books have greater effects on society than TV does.考题出现历次时间:2008-9-27NA,2010-3-13CN,2011-10-20CN答题思路:Two-way BrainstormingPrinted booksPrinted books have more educated effect on peoplePrinted books can be kept for a long timePrinted books are intangible cultural heritageTelevisionPrinted books is less vivid than televisionTelevision has effects on a wide range of peopleBooks is easily destroyed with the passing of timeModel Answer:Printed booksGorky once said,‘books are the stepping stones to human progress.Nowadays,with the development of technology,television also begins to influence people's life.People argue on the problem that whether printed books have greater effects on society than television has.Although television on is more technological advanced than printed books,I strongly believe that printed books have greater effects on society than television does.First and foremost,printed books have more educate effect on people.When reading a printed book,no matter a novel or a test book,people read,think and Sam idea.Especially when students read a test book they study theories and principles and then do after-work exercises.They gain more from printed books.When watching television'some students may only concentrate on the entertainment content regardless of the educated part.Margined knowledge is memorized,but not the key and educated principle.Secondly,printed books can be kept for a long time.Many ancient books are still kept in the museum.The essence of books that arc even1000years ago still educates contemporary people. Some television programs such as knowledge education program are influential on society.But these programs are easily forgettable and it is hard to keep the program.For example,if you wantto review one television program that you watched before,it is difficult to find it.On the contrary, printed books arc on your bookshelf all the time.Thirdly,primed books arc intangible cultural heritage.Many books especially ancient books by intelligent theorists are regarded as cultural heritage by government culture section.These books from content to form are more influential on society than television has.On this perspective, television is rarely seen as cultural heritage.Mostly,television is a kind of entertainment tool.In conclusion,primed books as intangible cultural heritage arc more educated and can be kept for a long time.Therefore,printed books have greater effects on society than television has.考题第一次出现时间:2012-4-20NA题目:Contributes on an enjoyable vacation,please select one of three selection.Good food, Good location and with good friends to travel.考题出现历次时间:2012-4-20NA,2012-4-20CN,2013-4-14CN考题第一次出现时间:2008-10-25NA题目:Do you agree or disagree with the following statement:Students who keep their rooms neat and organized are more successful than those who do not.考题出现历次时间:2008-10-25NA,2010-7-24CN考题第一次出现时间:2008-1-5CN题目:It is better for people to have friends who are intelligent than to have friends who have a good sense of humor.考题出现历次时间:2008-1-5CN,2013-11-2CN考题第一次出现时间:2008-3-14NA题目:Do you agree or disagree with the following statement:The environmental issue is too complex to be solved by the individuals.考题出现历次时间:2008-3-14NA,2010-1-23CN答题思路:Introduction(disagree)Many environmental problems can be solved on the individual level or through individual efforts. Main Body1Individuals can help to reduce global warming.•Using public transport is a good idea.•There are many ways to save electricity.Main Body2Individuals can play a part in controlling pollution•Smoking is a habit that releases pollutant•Dumping garbage hurts the environment.Main Body3It is essential to raise ecological consciousness.•We can learn how to recycle on a daily basis.•We can teach kids the importance of trees.Conclusion•By promoting environmental awareness and improving daily habits,individuals can help solvesome big problems.口语答案:One of the main daily grouses are most of the environmental issues are too complex today so individuals can do nothing about them.However to my way of thinking many environmental problems can be solved on the individual level or through individual efforts.At first,even though individual's capability counts for little it can also make a big difference when individuals gather to be a group.Take global warming as an example;individuals can reduce its effects by using public transport on a large scale and saving electricity as much as possible.Many a little will eventually make a miracle.Secondly,individuals can work effectively to improve local environment because they can play a part in controlling pollution.To name a few,smoking is a habit that releases pollutants;dumping garbage also does great harm to the environment.It these environmentally unfriendly behavior are effectively reduced,we can enjoy a more beautiful environment and even better life. Finally,it is essential to raise ecological consciousness because individuals will never be able to mark their victory until they manage to motivate more and more people to join environmental protection.For example,we can encourage each other to learn how to recycle on a daily basis and teach kids the importance of preserving forests.In conclusion,although large scale problems will remain severe,by promoting environmental awareness and improving daily habits,individuals can help solve some big problems little by little.考题第一次出现时间:2008-5-16NA题目:Do you agree or disagree with the following statement:Telephone has greater influence on people's lives than TV.考题出现历次时间:2008-5-16NA,2010-8-21CN答题思路:Introduction(agree)•Although television is a relatively recent invention,I believe that telephone influences our daily lives in a more profound way than television.Main Body1Telephone can reach far more places than television•People in remote villages have telephone servicesBut they do not have TV because it Telephone has improved their quMain Body2Telephone is a two-way communication tool•People can exchange ideas and feelings freely.•It is used an interactive tool in many workplaces.In contrast,watching TV is largely passive.Main Body3Cell phones continue to revolutionize human life.•Compared with phones,they are more powerful.•They expand our mobility and social life.•The iPhone craze has swept across the globe.Conclusion•Telephone is more influential than television as this two-way and far-reaching invention haschanged our lives more fundamentally.口语答案:Although television is a relatively recent invention,I believe that telephone which influences our daily lives in a more profound way has a clear edge over television.To start with,on account of its high mobility,telephone can reach far more places than television. Most obviously,people in remote villages cannot do without telephone services yet they hardly need TV because they consider it a luxury in comparison with telephone.Indeed telephone plays a more striking role in some emergency cases and TV cannot be mentioned in the same breath.Secondly,telephone is a two-way communication tool while TV can never do.That is to say,telephone can not only be used to exchange ideas and share feelings freely but also functions as an interactive tool in many work places.For example,when discussing important and urgent issue with our customers or business partners,making a call is always timely and effective.In contrast,watching TV is largely passive and we cannot have any interaction with others through it. Finally,cell phones,especially the emerging smart phones are continuing to revolutionize human life.Clearly,compared with traditional phones,they are more powerful since they expand our mobility and social life.Take the iPhone as an example,the craze for it has swept across the globe and the fans even line up overnight in order to buy one.Its success lies in the fact that it provides a wider choice of communication and entertainment for contemporary people.In conclusion,Telephone is more influential than television as this two-way and far-reaching invention has changed our lives more fundamentally.考题第一次出现时间:2012-4-14NA题目:Do you agree or disagree,it is important for government to protect wild animals and wilderness areas for future generation.考题出现历次时间:2012-4-14NA,2012-4-14CN答题思路:Introduction(agree)•Animals and wilderness areas are an important part of our ecology that needs strong protection. Main Body1Wildlife conservation is a government duty.•Extinction of rare species is intolerable.•Humans would be too lonelyMain Body2Wilderness areas are an important part of nature,without animals.They provide natural habitats for species,without animals.Main Body3Such protection is good for our living environment.•It creates biodiversity around the world.•More plants help to reduce global warming.Conclusion•The benefits of protecting animals and wilderness areas areenormous,and any government should be aware of it.口语答案:As individuals,our power and strength are too limited to make any count,and thus,from my perspective,it is important for government to protect animals and wilderness areas because they are an important part of our ecology that needs strong protection.First of all,wildlife conservation is a government duty rather than individuals.With increasing ecological consciousness,neither people nor have realized that extinction of rare species is intolerable.It is not hard to imagine that if animals perished,humans would be too lonely. Therefore,government should be clear about us obligation protect wild animals.In the second place,wilderness areas are an important part of nature easy to understand that wilderness areas provide natural habitats for species,especially some rare species such as red-crowned cranes and Siberian tigers.With some endangered species better protected,human can maintain the ecological balance in a better way instead of watching some precious biological species die out. Finally,it’s absolutely necessary to protect the wild animals and wilderness areas for our living environment.As is known to all,a balanced ecosystem helps create biodiversity around the world. Besides,more plants can help to reduce global warming,which is now a global crisis.In fact,if the government can enact some relevant laws,individuals can be armed with stronger weapons to fight against environmental crimes.In conclusion,the benefits of protecting animals and wilderness areas are enormous and closely connected to the sound and sustainable development of a country,so any government should be aware of the importance of protecting ecological environment考题第一次出现时间:2012-7-22CN题目:Do you agree or disagree with the following opinion?The most important goal of education is to help people educate themselves?考题出现历次时间:2012-7-22CN,2013-6-14NA答题思路:Two-way BrainstormingAgree:Teachers cannot be everywhere and anytime.Self-study is the most useful and efficient studying skill.Self-study is of great help,in the future career.Disagree:For individual,the goal of education is to apply the knowledge.For country,the goal of education is to create a more prosperous nation.Admittedly,the goal of education depends on different objects.口语答案:Model Answer:The purpose of education is always been disputed by people.Recently,some people proposed that the most important goal of education is to help people educate themselves I am totally agreed with this opinion because self-study should be put in a primary rote.First and foremost,teachers cannot be everywhere and anytime and you cannot rely on others for the whole life.AS old saying said one is never too old to learn.Study is a life-long career.When we are at school,most of the teacher teaches us.But after we leave the school and come into the society.Who can teach us?Teachers are just guiders not mammies with us everywhere and at any time.Secondly,self-study is the most useful and efficient studying skill.When we are at junior and senior school,the primary goal of education is to get high marks,then entering celebrateduniversity.But that is only part of cation is not just high marks.More importantly, education is a continuous and self-improvement process.According to this,the eventual goal of education is to teacher people how to self-improvement.Obviously,teaching people to educate themselves is the best method.In the self-study process,people gather and understand information in a syntaxes way that is more efficient than Duck-stuffing teaching.Last but not least,self-study is of great help in the future career.After graduation,we do not have many chances to study like in school in a systematic way.But working also need continuous development.To achieve the specific goal in career,people have to team to educate themselves. For example,if you are doing a human resources job,you want to get a related certificate in your field for future promotion.At this condition,the importance of self-study is obvious.In conclusion, education is a life-long career.It is not only at school but also after school.So for education,the most important role is not the teachers,but the students.Teachers arc only guiders.Students should learn the self-study ability in the long period.考题第一次出现时间:2013-2-2NA题目:During times of economic crisis,which area of spending do you think the government should reduce:education,healthcare or support for the unemployed?答题思路:Three-way BrainstormingEducationcation can be sponsored by private corporations.cation involves fewer civilians.cational institutions can raise tuition fees.Healthcare1.Healthcare can be sponsored by private corporations.2.Healthcare can be improved by the higher awareness of personal sanitation.3.Healthcare organizations can raise medical fees.Unemployed1.The unemployed can be sponsored by Private Corporation.2.The unemployed involves fewer civilians.3.The unemployed should voluntarily raise their working skills.口语答案:Model Answer:EducationAs more and more financial crises happen in different continents,many national leaders have established proper policies to make up the loss and stabilize the economy.Among three popular ways,the fewer budgets for education,healthcare,and the unemployed,I prefer the first one for three following reasons.First education can be sponsored by private corporations.As we all know,most universities in different countries are supported by the government not only in teachers’salary but also in research funds.However because some top universities such as Columbia Universities and Harvard University are sponsored by private companies,it is quite possible that more public universities can be covered into private mechanism that even can improve academic reputation.Thus,reducing expenses on education is a proper solution to economic crisis.Second,education involves fewer civilians,which means fewer negative impacts on education that are made by fewer budgets from thegovernment.As we all know,people whose age between8and22are the main components of targets for education.That is to say,these people are only a relatively small part of the whole population.So,it is reasonable that reducing the money on education is a better way for the government to overcome the tough time.Third,educational institutions can raise tuition fees to respond to the less governmental spending on education.As we all know,most parents are willing to pay for the fees for the promising future of their children.That is,when schools and universities can receive enough money from students and parents to balance the cost of operation,government can minimize the side effect of fewer budgets for education.In a word,although education is important to the successful development of a country,it should be weighed less when the government makes a decision to relieve the economic crisis.Fortunately,education has its own mechanism to recover.考题第一次出现时间:2013-2-23NA题目:In order to attract good students,many university spent a lot of money in society activities,do you agree or disagree答题思路:Introduction(disagree)•Although society activities are quite important,they are under no circumstance the only aspect that should be used by universities to capture excellent students.Main Body1Universities should lay more stores by the academic staff faculty members.•Outstanding teachers can create good academic atmosphere.They are more likely to make teaching achievement.It is easier for students to admire the talents.Main Body2Hardware facilities are another factor that should be taken seriously.•Advanced multimedia classrooms can improve teaching efficiency.Comfortable dwelling and dining places are indispensable to students.•Modem gymnasium definitely deserves emphasis from universities.Main Body3Vocational matters of students are too essential to be ignored.•Employment of students is related to the future of universities.•High employment rate helps to establish the reputation for schools.•By no means should universities decrease the significance of employment.Conclusion•Apart from society activities,there are many other aspects that need to be attached much importance,such as facultystrength,physical infrastructure and employment issue.口语答案:Nowadays…the conviction that in order to attract good students,a university should spend a lot of money funding social activities is gaining strength.However,from my point of view,although society activities are quite important,they are under no circumstance the only aspect that should be used by universities to excellent students.At first,universities should lay more stores by the academic staff and faculty members.Beyond alldoubt,outstanding teachers can create good academic atmosphere.The teachers with professional knowledge are more likely to be admired by the students and stimulate their interest in learning.In the second place,hardware facilities are another factor that should be taken seriously because they highlight the determination of a school to improve it and create a sound living and studying environment for students.For example,advanced multimedia classrooms can improve teaching efficiency;comfortable dwelling and dining places put students in a good mood to live;working out in a modem gymnasium help students build up their physique.Last but not least,vocational matters of students are too essential to be ignored by the university. It must be pointed out that the employment of students is related to the future of universities and high employment rate helps to establish the reputation for schools.Thus,by no means should universities decrease the significance of employment.Otherwise,it will lead the universities to a dead endIn conclusion,faculty strength,physical infrastructure and employment issue are all indispensable to the sustainable development of universities and all of them should take priority over the society activities.考题第一次出现时间:2013-3-2NA题目:Do you agree or disagree with the following statement?People should state their honest opinions even though they know others will disagree with their views.答题思路:Two-way BrainstormingAgree1.Honesty is one of the most important characters in any relationship.2.Expressing you honest opinions offers a chance to get refinement.3.The discussion on your honest opinions can improve the ability of argument and communication.Disagree1.Stating honest opinions may reflect our ignorance.2.Stating honest opinions may hurt other people.3.Stating honest opinions sometimes raises more enemies.口语答案:Model Answer:AgreeIn this complicated society,more people choose to wear marks to adapt themselves to the dusty world.Thus,it is common that some people hide their honest opinions because they are incompatible with the majorities'Nevertheless,I prefer to be honest even if I know many people will be against me.To start with,honesty is one of the most important characters in any relationship.As we all known,real friendship and true family bond are based on trust.Hiding your real thought can be a seed for conflict or even the betrayal.Telling the truth even if others disagree with them will definitely let others know that you are an honest guy.As a result,they want to make true friends with you.Secondly,if you express honest opinions that are not admitted by others,you own a chance to exam your honest opinions.It is not exaggerated to say that in most situations,when you know your honest ideas will be rejected by others,you must have some problems on your own.To state。
2023年公共英语四级阅读模考试题及答案2023年公共英语四级阅读模考试题及答案Use a dictionary and grammar guide constantly. Keep a small English dictionary with you at all time. When you see a new word, look it up. Think about the word-- use it, in your mind, in a sentence.以下是我为大家搜寻整理的2023年公共英语四级阅读模考试题及答案,期望能给大家带来帮忙!更多精彩内容请准时关注我们应届毕业生考试网!The percentage of immigrants (including those unlawfully present) in the United states has been creeping upward for years. At 12.6 percent, it is now higher than at any point since the mid1920s.We are not about to go back to the days when Congress openly worried about inferior races polluting America’s bloodstream. But once again we are wondering whether we have too many of the wrong sort newcomers. Their loudest critics argue that the new wave of immigrants cannot, and indeed do not want to, fit in as previous generations did.We now know that these racist views were wrong. In time, Italians, Romanians and members of other so-called inferior races became exemplary Americans and contributed greatly, in ways too numerous to detail, to the building of this magnificent nation. There is no reason why these new immigrants should not have the same success.Although children of Mexican immigrants do better, in terms of educational and professional attainment, than their parents U CLA sociologist Edward Telles has found that the gains don’t continue. Indeed, the fouth generation is marginally worse off than the third James Jackson, of the University of Michigan, has found a similar trend among black Caribbean immigrants, Tells fears that Mexican-Americans may be fated to follow in the footsteps of American blacks-that large parts of the community may become mired(陷入)in a seemingly permanent state of poverty and Underachievement. Like African-Americans, Mexican-Americans are increasingly relegated to (降入)segregated, substandard schools, and their dropout rate is the highest for any ethnic group in the country.We have learned much about the foolish idea of excluding people on the presumption of the ethnic/racial inferiority. But what we have not yet learned is how to make the process of Americanization work for all. I am not talking about requiring people to learn English or to adopt American ways; those things happen pretty much on their own, but as arguments about immigration hear up the campaign trail, we also ought to ask some broader question about assimilation, about how to ensure that people , once outsiders , don’t forever remain marginalized within these shores.That is a much larger question than what should happen with undocumented workers, or how best to secure the border, and it is one that affects not only newcomers but groups that have been here for generations. It will have more impact on our future than where we decide to set the admissions bar for the latest ware of would-be Americans. And it would be nice if we finallygot the answer right.1. How were immigrants viewed by U.S. Congress in early days?A) They were of inferior races.B) They were a Source of political corruption.C) The y were a threat to the nation’s security.D) They were part of the nation’s bloodstream.2. What does the author think of the new immigrants?A) They will be a dynamic work force in the U.S.B) They can do just as well as their predecessors.C) They will be very disappointed on the new land.D) They may find it hard to fit into the mainstream.3. What does Edward Telles’ research say aboutMexican-Americans?A) They may slowly improve from generation to generation.B) They will do better in terms of educational attainment.C) They will melt into the African-American community.D) They may forever remain poor and underachieving.4. What should be done to help the new immigrants?A) Rid them of their inferiority complex.B) Urge them to adopt American customs.C) Prevent them from being marginalized.D) Teach them standard American English.5. According to the author, the burning issue concerning immigration is_______.A) How to deal with people entering the U.S. without documentsB) How to help immigrants to better fit into American societyC) How to stop illegal immigrants from crossing the borderD) How to limit the number of immigrants to enter the U.S.参考答案:ABDCB文档内容到此结束,欢迎大家下载、修改、丰富并分享给更多有需要的人。
高二年级英语国际关系与国际法基础单选题50题1. When a country respects the territorial integrity of other nations, it is mainly upholding the principle of _.A. diplomatic immunityB. national sovereigntyC. international tradeD. cultural exchange答案:B。
解析:国家主权(national sovereignty)包含国家领土完整等多方面的要素,一个国家尊重他国领土完整就是在维护国家主权原则。
外交豁免(diplomatic immunity)主要是关于外交人员在驻在国的特殊权利等,与领土完整无关,A选项错误。
国际贸易international trade)侧重于国家间的商业往来,C选项不符合题意。
文化交流(cultural exchange)主要涉及文化方面的互动,和领土完整没有直接关系,D选项也不正确。
2. In international relations, the exchange of ambassadors between two countries is a sign of _.A. military allianceB. diplomatic relationsC. economic dependenceD. cultural domination答案:B。
解析:两国之间互派大使是建立外交关系(diplomatic relations)的典型标志。
军事联盟(military alliance)是基于军事合作的关系,与互派大使不完全等同,A选项错误。
经济依赖(economic dependence)强调经济方面的联系,和互派大使的关系不大,C选项不合适。
文化统治(cultural domination)与互派大使所代表的外交关系概念不同,D选项错误。
base important policies on the best judgmentThere are several reasons why it is important to base important policies on the best judgment:1. Expertise and experience: Policy decisions should be made based on the expertise and experience of the individuals involved. This ensures that the decision-makers have a deep understanding of the subject matter and can make sound judgments based on their knowledge.2. Evidence-based approach: Basing policies on the best judgment means taking into account empirical evidence, research, and data. This helps to ensure that policies are grounded in facts and have a higher chance of being effective and achieving their intended outcomes.3. Flexibility: Policies based on the best judgment allow for flexibility and adaptability. They do not rely solely on rigid rules and regulations but instead allow decision-makers to consider multiple factors and adapt the policies as needed.4. Contextual considerations: The best judgment takes into account the specific context and realities of the situation at hand. This allows decision-makers to consider the unique needs and challenges of a particular situation or group of people, leading to policies that address these specificities effectively.5. Ethical considerations: Policy decisions based on the best judgment ensure that ethical considerations are taken into account. This includes considering the potential impact on variousstakeholders, promoting fairness and justice, and ensuring that policies align with ethical principles and values.It is important to note that the best judgment should be informed by a multitude of perspectives, expertise, and diverse voices. Decision-makers should seek input from experts, stakeholders, and affected communities to ensure that policies are well-rounded and consider a wide range of perspectives.。
a r X i v :c s /0405111v 2 [c s .C R ] 27 N o v 2004Attrition Defenses for a Peer-to-Peer Digital Preservation SystemTJ GiuliStanford University,CAPetros ManiatisIntel Research,Berkeley,CAMary BakerHP Labs,Palo Alto,CADavid S.H.RosenthalStanford University Libraries,CAMema RoussopoulosHarvard University,Cambridge,MAAbstractIn peer-to-peer systems,attrition attacks include both traditional,network-level denial of service attacks as well as application-level attacks in which malign peers conspire to waste loyal peers’resources.We describe several defenses for LOCKSS,a peer-to-peer digital preservation system,that help ensure that application-level attacks even from powerful adversaries are less effective than simple network-level attacks,and that network-level attacks must be intense,wide-spread,and prolonged to impair the system.$Revision: 1.317$1IntroductionDenial of Service (DoS)attacks are among the most dif-ficult for distributed systems to resist.Distinguishing le-gitimate requests for service from the attacker’s requests can be tricky,and devoting substantial effort to doing so can easily be self-defeating.The term DoS was in-troduced by Needham [32]with a broad meaning but over time it has come to mean high-bit-rate network-level flooding attacks [22]that rapidly degrade the usefulness of the victim system.In addition to DoS,we use the term attrition to include also moderate-or low-bit-rate application-level attacks that gradually impair the victim system.The mechanisms described in this paper are aimed at equipping the LOCKSS 1peer-to-peer (P2P)digital preservation system to resist attrition attacks.The sys-tem is in use at about 80libraries worldwide;publishers of about 2000titles have endorsed its use.Cooperation among peers reduces the cost and increases the reliabil-ity of preservation,eliminates the need for backup,and greatly reduces other operator interventions.A loyal (non-malign)peer participates in the LOCKSS system for two reasons:to achieve regular reassurancecrux of attrition attacks and their defenses,we extend our prior evaluation[29]to deal with numerous con-currently preserved archival units of content competing with each other for resources.Finally,resource over-provisioning is essential in defending against attrition attacks.Our contribution is the ability to put an upper bound on the amount of over-provisioning required to defend the LOCKSS system from an arbitrarily power-ful attrition adversary.Our defenses may not all be im-mediately applicable to all P2P applications,but we be-lieve that many systems may benefit from a subset of de-fenses,and that our analysis of the effectiveness of these defenses is more broadly useful.In the rest of this paper,wefirst describe our applica-tion.We continue by outlining how we would like this application to behave under different levels of attrition attack.We give an overview of the LOCKSS protocol, describing how it incorporates each of our attrition de-fenses.We then explain the results of a systematic explo-ration of simulated attacks against the resulting design, showing that it successfully defends against attrition at-tacks at all layers,from the network level up through the application protocol.2The ApplicationIn this section,we provide an overview of the digital preservation problem for academic publishing,the prob-lem that LOCKSS seeks to solve.We then present and justify the set of design goals required of any solution to this problem,setting the stage for our approach in subse-quent sections.Academic publishing has migrated to the Web[42], placing society’s scientific and cultural heritage at a vari-ety of risks such as confused provenance,accidental edit-ing by the publisher,storage corruption,failed backups, government or corporate censorship,vandalism,and de-liberate rewriting of history.The LOCKSS system was designed[36]to provide librarians with the tools they need to preserve their community’s access to journals and other Web materials.Any solution must meet six stringent requirements. First,since under US law[16]copyright Web content can only be preserved with the owner’s permission,the so-lution must accommodate the publishers’interests.Re-quiring publishers,for example,to offer perpetual no-fee access or digital signatures on content makes them reluctant to give that permission.Second,a solution must be extremely cheap in terms of hardware,operating cost,and human expertise.Few libraries could afford[3] a solution involving handling and securely storing off-line media,but most can afford the few cheap off-the-shelf PCs that provide sufficient storage for tens of thou-sands of journal-years.Third,the existence of cheap,reliable storage cannot be assumed;affordable storage is unreliable[21,35].Fourth,a solution must have a long time horizon.Auditing content against stored dig-ital signatures,for example,assumes not only that the cryptosystem will remain unbroken,but also that the se-crecy,integrity,and availability of the keys are guaran-teed for decades.Fifth,a solution must anticipate ad-versaries capable of powerful attacks sustained over long periods;it must withstand these attacks,or at least de-grade slowly and gracefully while providing unambigu-ous warnings[34].Sixth,a solution must not require a central locus of control or administration,if it is to with-stand concentrated technical or legal attacks.Two different architectures have been proposed for preserving Web journals.On one hand,trusted third party archives require publishers to grant the archive per-mission,under certain circumstances,to republish their content.It has proved very difficult to persuade pub-lishers to do so[5].In the LOCKSS system,on the other hand,publishers need only grant their subscribing libraries permission to supply their own content replica to their local readers.This has been the key to obtaining permission from publishers.It is thus important to note that our goal is not to minimize the number of replicas consistent with content safety.Instead,we strive to min-imize the per-replica cost of maintaining a large number of replicas.We trade extra replicas for fewer lawyers,an easy decision given their relative costs.The LOCKSS design is extremely conservative,mak-ing few assumptions about the infrastructure.Although we believe this is appropriate for a digital preservation system,less conservative assumptions are certainly pos-sible.Taking increased risk can increase the amount of content that can be preserved with given computa-tional power.For example,the availability of limited amounts of reliable,write-once memory would allow au-dits against local hashes,the availability of a reliable public key infrastructure might allow publishers to sign their content and peers to audit against the signatures, and so on.Conservatively,the assumptions underlying such optimizations could be violated without warning at any time;the write-once memory might be corrupted or mishandled or a private key might leak.Thus,designs us-ing these optimizations would still need the audit mech-anism as a fall-back.The more a peer operator can do to avoid local failures the better the system works,but our conservative design principles lead us to focus on mech-anisms that minimize dependence on these efforts. With this specific application in mind,we tackle the “abstract”problem of auditing and repairing replicas of distinct archival units or AUs(a year’s run of an on-line journal,in our target application)preserved by a popu-lation of peers(libraries)in the face of attrition attacks. For each AU it preserves,a peer starts out with its own,correct replica(obtained from the publisher’s Web site), which it can only use to satisfy local read requests(from local patrons)and to assist other peers with replica re-pairs.In the rest of this paper we refer to AUs,peers, and replicas,rather than journals and libraries.3System ModelIn this section we present the adversary we model,our security goals for the system,and our defensive frame-work.3.1Adversary ModelIn keeping with our conservative design philosophy,we assume a powerful adversary with several important abil-ities.Pipe stoppage is his ability to prevent communi-cation with victim peers for extended periods byflood-ing links with garbage packets or using more sophisti-cated techniques[25].Total information awareness al-lows him to control and monitor all of his resources in-stantaneously.He has unconstrained identities in that he can purchase or spoof unlimited network identities.In-sider information allows him complete knowledge of his victims’system parameters and resource commitments. Masquerading means that loyal peers cannot detect him, as long as he follows the protocol.Finally,he has unlim-ited computational resources,though he is polynomially bounded in his computations(i.e.,he cannot invert cryp-tographic functions).The adversary employs these capabilities in effortless and effortful attacks.An effortless attack requires no measurable computational effort from the attacker and includes traditional DoS attacks such as pipe stoppage. An effortful attack requires the attacker to invest in the system and therefore requires computational effort. 3.2Security GoalsThe overall goal of the LOCKSS system is to maintain a high probability that the consensus of peers reflects the correct AU,and a high probability that a reader accesses good data.In contrast,an attrition adversary’s goal is to decrease these probabilities significantly by preventing peers from auditing their replicas for a long time,long enough for undetected storage problems such as“bit rot”to occur.Severe pipe stoppage attacks in the wild last for days or weeks[31].Our goal is to ensure that,in the very least,the LOCKSS system withstands such attacks sus-tained over months.Beyond pipe stoppage,attackers must use protocol messages to some extent.We seek to ensure the following three conditions.First,a peer man-ages its resources so as to prevent exhaustion no matter how much effort is exerted by however many identities request service.Second,when deciding which requests to service,a peer gives preference to requests from those likely to behave properly(i.e.,“ostensibly legitimate”). And third,at every stage of a protocol exchange,an os-tensibly legitimate attacker expends commensurate effort to that which he imposes upon the defenders.3.3Defensive FrameworkWe seek to curb the adversary’s success by modeling a peer’s processing of inbound messages as a series of filters,each costing a certain amount to apply.A mes-sage rejected by afilter has no further effect on the peer, allowing us to estimate the cost of eliminating whole classes of messages from further consideration.Eachfil-ter increases the effort a victim needs to defend itself,but limits the effectiveness of some adversary capability. The bandwidthfilter models a peer’s network connec-tion.It represents the physical limits on the rates of inbound messages that an adversary can force upon his victims.The admission controlfilter takes inbound mes-sages at the maximum rate supported by the bandwidth filter and further limits them to match the maximum rate at which a peer expects protocol traffic from legitimate senders,favoring known peer identities.This curbs the adversary’s use of unlimited identities and prevents him from applying potentially unconstrained computational resources upon a victim.The effort balancingfilters en-sure that effort imposed upon a victim by ostensibly le-gitimate traffic is balanced by correspondingly high ef-fort borne by the attacker,making it costly for a resource-constrained adversary to masquerade as a legitimate peer. We show in Section7.4that the most effective strat-egy for effortful attacks is to emulate legitimacy,and that even this has minimal effect on the utility of the system. Effortless attacks,such as traditional distributed DoS (DDoS)attacks,are more effective but must be main-tained for a long time against most of the peer population to degrade the system significantly(Section7.2).4The LOCKSS Replica Auditing and Re-pair ProtocolThe LOCKSS audit process operates as a sequence of “opinion polls”conducted by every peer on each of its AU replicas.At intervals,typically every3months,a peer(the poller)constructs a random subset(i.e.,sam-ple)of the peer population that it knows are preserv-ing an AU,and invites those peers as voters into a poll. Each voter individually hashes a poller-supplied nonce and its replica of the AU to produce a fresh vote,which the poller tallies.If the poller is outvoted in a landslide (e.g.,it disagrees with80%of the votes),it assumes itsFigure1:A time-line of a poll,showing the message exchange between the poller and a voter.replica is corrupt and repairs it from a disagreeing voter. The roles of poller and voter are distinct,but every peer plays both.The general structure of a poll follows the time-line of Figure1.A poll consists of two phases:the vote solici-tation phase and the evaluation phase.In the vote solic-itation phase the poller requests and obtains votes from as many voters in its sample of the population as pos-sible.Then the poller begins the evaluation phase,dur-ing which it compares these votes to its own replica,one hashed content block at a time,and tallies them.If the hashes disagree the poller may request repair blocks from its voters and re-evaluate the block.If in the eventual tally,after any repairs,the poller agrees with the land-slide majority,it sends a receipt to each of its voters and immediately starts a new poll.Peers interleave making progress on their own polls and voting in other peers’polls,spreading each poll over a long period chosen so that polls on a given AU occur at a rate much higher than the rate of undetected storage problems,e.g.“bit rot.”4.1Vote SolicitationThe outcome of a poll is determined by the votes of the inner circle peers,sampled at the start of the poll by the poller from its reference list for the AU.The reference list contains mostly peers that have agreed with the poller in recent polls on the AU,and a few peers from its static friends list,maintained by the poller’s operator.A poll is considered successful if its result is based on a minimum number of inner circle votes,the quorum, which is typically10,but may change according to the application’s needs for fault tolerance.To ensure that a poll is likely to succeed,a poller invites into its poll a larger inner circle than the quorum(typically,twice as large).If atfirst try,an inner circle peer fails to respond to an invitation,or refuses it,the poller contacts a different inner circle voter,re-trying the reluctant peer later in the same vote solicitation phase.An individual vote solicitation consists of four mes-sages(see Figure1):Poll,PollAck,PollProof,and Vote. For the duration of a poll,a poller establishes an en-crypted TLS session with each voter individually,via an anonymous Diffie-Hellman key exchange.Every proto-col message is conveyed over this TLS session,either keeping the same TCP connection from message to mes-sage,or resuming the TLS session over a new one.The Poll message invites a voter to participate in a poll on an AU.The invited peer responds with a PollAck mes-sage,indicating either a refusal to participate in the poll at the time,or an acceptance of the invitation,if it can compute a vote within a predetermined time allowance. The voter commits and reserves local resources to that effect.The PollProof message supplies the voter with a random nonce to be used during vote construction.To compute its vote,the voter uses a cryptographic hash function(e.g.,SHA-1)to hash the nonce supplied by the poller,followed by its replica of the AU,block by block. The vote consists of the running hashes produced at each block boundary.Finally,the voter sends its vote back to the poller in a Vote message.These messages also contain proofs of computational effort,such as those introduced by Dwork et al.[15], sufficient to ensure that,at every protocol stage,the re-quester of a service has more invested in the exchange than the supplier of the service(see Section5.1).4.2Peer DiscoveryThe poller uses the vote solicitation phase of a poll not only to obtain votes for the current poll,but also to dis-cover new peers for its reference list from which it can solicit inner circle votes in future polls.Discovery is effected via nominations included in Vote messages.A voter picks a random subset of its cur-rent reference list,which it includes in the Vote message. The poller accumulates these nominations.When it con-cludes its inner circle solicitations,it chooses a random sample of these nominations as its outer circle.It pro-ceeds to solicit regular votes from these outer circle peers in a manner identical to that used for inner circle peers. The purpose of the votes obtained from outer circle voters is to show the“good behavior”of newly discov-ered peers.Those who perform correctly,by supplying votes that agree with the prevailing outcome of the poll, are added into the poller’s reference list at the conclu-sion of the poll;the outcome of the poll is computed only from inner-circle votes.4.3Vote EvaluationOnce the poller has accumulated all votes it could obtain from inner and outer circle voters,it begins the poll’s evaluation phase.During this phase,the poller computes,in parallel,all block hashes that each voter should have computed,if that voter’s replica agreed with the poller’s.A vote agrees with the poller on a block if the hash in the vote and that computed by the poller are the same.For each hash computed by the poller for an AU block, there are three possibilities:first,the landslide majority of inner-circle votes(e.g.,80%)agree with the poller;in this case,the poller considers the audit successful up to this block and proceeds with the next block.Second,the landslide majority of inner-circle votes disagree with the poller;in this case,the poller regards its own replica of the AU as damaged,obtains a repair from one of the dis-agreeing voters(via the RepairRequest and Repair mes-sages),and reevaluates the block hoping tofind itself in the landslide majority,as above.Third,if there is no landslide majority of agreeing or disagreeing votes,the poller deems the poll inconclusive,raising an alarm that requires attention from a human operator. Throughout the evaluation phase,the poller may also decide to obtain a repair from a random voter,even if one is not required(i.e.,even if the corresponding block met with a landslide agreement).The purpose of such frivolous repairs is to prevent targeted free-riding via the refusal of repairs;voters are expected to supply a small number of repairs once they commit to participate in a poll,and are penalized otherwise(Section5.1).If the poller hashes all AU blocks without raising an alarm,it concludes the poll by sending an evaluation re-ceipt to each voter(with an EvaluationReceipt message), indicating that it will not be requesting any more repairs. The poller then updates its reference list by removing all voters whose votes determined the poll outcome and by inserting all agreeing outer-circle voters and some peers from the friends list(for details see[29]).The poller then restarts a poll on the same AU,scheduling it to conclude an inter-poll interval into the future.5LOCKSS DefensesHere we outline the attrition defenses of the LOCKSS protocol:admission control,desynchronization,and re-dundancy.These defenses raise system costs for both loyal peers and attackers,but favor ostensible legiti-macy.Given a constant amount of over-provisioning, loyal peers continue to operate at the necessary rate re-gardless of the attacker’s power.Many systems over-provision resources to protect performance from known worst-case behavior(e.g.,the Unixfile system[30]). 5.1Admission ControlThe purpose of the admission control defense is to ensure that a peer can control the rate at which it considers poll invitations from others,favoring invitations from those who operate at roughly the same rate as itself and pe-nalizing others.We implement admission control using three mechanisms:rate limitation,first-hand reputation, and effort balancing.Rate Limitation:Without limits on the rate at which they attempt to service requests,peers can be over-whelmed byfloods of ostensibly valid requests.Rate Limitation suggests that peers should initiate and sat-isfy requests no faster than necessary rather than as fast as possible.Because readers access only their lo-cal LOCKSS peer,the audit and repair protocol is not subject to end-users’unpredictable request patterns.The protocol can proceed at its own pace,providing an inter-esting test case for rate limitation.We identify three possible attacks based on deviation from the necessary rate of polling.A poll rate adversary would seek to trick victims into either decreasing(e.g., by causing back-off behavior)or increasing(e.g.,in an attempt to recover from a failed poll)their rate of calling polls.A pollflood adversary would seek,under a multi-tude of identities,to invite victims into as many frivolous polls as possible hoping to crowd out the legitimate poll requests and thereby reduce the ability of loyal peers to audit and repair their content.A voteflood adversary would seek to supply as many bogus votes as possible hoping to exhaust loyal pollers’resources in useless but expensive proofs of invalidity.Peers defend against all these adversaries by setting their rate limits autonomously,not varying them in re-sponse to other peers’actions.Responding to adversity (inquorate polls or perceived contention)by calling polls more frequently could aggravate the problem;backing off to a lower rate of polls would achieve the adversary’s aim of slowing the detection and repair of damage;Kuz-manovic et al.[25]describe a similar attack in the context of TCP retransmission timers.Because peers do not re-act,the poll rate adversary has no opportunity to attack. The price of thisfixed rate of operation is that,absent manual intervention,a peer may take several inter-poll intervals to recover from a catastrophic storage failure. The pollflood adversary tries to get victims to over-commit their resources or at least to commit excessively to the adversary.To prevent over-commitment,peers maintain a task schedule of their promises to perform ef-fort,both to generate votes for others and to call their own polls.If the effort of computing the vote solicited by an incoming Poll message cannot be accommodated in the schedule,the invitation is refused.Furthermore, peers limit the rate at which they even consider poll invi-tations(i.e.,establishing a secure session,checking their schedule,etc.).A peer sets this rate limit for considering poll invitations according to the rate of poll invitations it sends out to others;this is essentially a self-clocking mechanism.We explain how this rate limit is enforced inthefirst-hand reputation description below.We evaluate our defenses against pollflood strategies in Section7.3. The voteflood adversary is hamstrung by the fact that votes can be supplied only in response to an invitation by the putative victim poller,and pollers solicit votes at afixed rate.Unsolicited votes are ignored.First-hand reputation:A peer locally maintains and usesfirst-hand reputation(i.e.,history)for other peers. Each peer P maintains a known-peers list,separately for each AU it preserves.The list contains an entry for ev-ery peer that P has encountered in the past,tracking its exchange of votes with that peer.The entry holds a rep-utation grade for the peer,which is one of three values: debt,even,or credit.A debt grade means that the peer has supplied P with fewer votes than P has supplied it.A credit grade means P has supplied the peer with fewer votes than the peer has supplied P.An even grade means that P and the peer are even in their recent exchanges of votes.Entries in the known-peers list“decay”with time toward the debt grade.In a protocol interaction,both the poller and a voter modify the grade they have assigned to each other de-pending on their respective behaviors.If the voter sup-plies a valid vote and valid repairs for any blocks the poller requests,then the poller increases the grade it has assigned to the voter(from debt to even,from even to credit,or from credit to credit)and the voter correspond-ingly decreases the grade it has assigned to the poller.If either the poller or the voter misbehave(e.g.,the voter commits to supplying a vote but does not,or the poller does not send a valid evaluation receipt),then the other peer decreases its grade to debt.This is similar to the re-ciprocative strategy of Feldman et al.[17],in that it pe-nalizes peers who do not reciprocate,i.e.,do not supply votes in return for the votes they receive.Peers randomly drop some poll invitations arriving from previously unknown peers and from pollers with a debt grade.Invitations from pollers with an even or credit grade are not dropped.This reputation system re-duces free-riding,as it is not possible for a peer to main-tain an even or credit grade without providing valid votes. To discourage identity whitewashing the drop probabil-ity imposed on unknown pollers is higher than that im-posed on known in-debt pollers.Furthermore,invitations from unknown or in-debt pollers are subject to a rigid rate limit;after it admits one such invitation for consid-eration,a voter enters a refractory period during which it automatically rejects all invitations from unknown or in-debt pollers.Like the known-peers list,refractory pe-riods are maintained on a per AU basis.Consequently, during every refractory period,a voter admits at most one invitation from unknown or in-debt peers,plus at most one invitation from each of its fellow peers with a credit or even grade.Since credit and even grades decay with time,the total“liability”of a peer in the number of in-vitations it must admit per refractory period is limited to a small constant number.As a result,the duration of the refractory period is inversely proportional to the rate limit imposed by the peer on the poll invitations that it considers for each AU it preserves.Continuous triggering of the refractory period can stop a victim voter from accepting invitations from unknown peers who are loyal;this can limit the choices a poller has in potential voters to peers that know the poller al-ready.To reduce this impediment to diversity,we in-stitute the concept of peer introductions.A peer may introduce peers that it considers loyal to others;peers introduced in this way can bypass random drops and re-fractory periods.Introductions are bundled along with nominations during the regular discovery process(Sec-tion4.2).Specifically,a poller randomly partitions the peer identities in a Vote message into outer circle nomi-nations and introductions.A poll invitation from an in-troduced peer is treated as if coming from a known peer with an even grade.This unobstructed admission con-sumes the introduction in such a way that at most one in-troduction is honored per(validly voting)introducer,and unused introductions do not accumulate.Specifically, when consuming the introduction of peer B by peer A for AU X,all other introductions of other introducees by peer A for AU X are“forgotten,”as are all introduc-tions of peer B for X by other introducers.Furthermore, introductions by peers who have entered and left the ref-erence list are also removed,and the maximum number of outstanding introductions is capped.Effort Balancing:If a peer expends more effort to re-act to a protocol message than the sender of that message did to generate and transmit it,then an attrition attack need consist only of aflow of ostensibly valid protocol messages,enough to exhaust the victim peer’s resources. We adapt the ideas of pricing via processing[15]to discourage such attacks from resource-constrained ad-versaries by effort balancing our protocol.We inflate the cost of a request by requiring it to include a proof of com-putational effort sufficient to ensure that the total cost of generating the request exceeds the cost to the supplier of both verifying the effort proof and satisfying the re-quest.We favor Memory-Bound Functions(MBF)[14] rather than CPU-bound schemes such as“client puz-zles”[12]for this purpose,because the spread in memory system performance is smaller than that of CPU perfor-mance[13].Note that an adversary with ample compu-tational resources is not hindered by effort balancing. Applying an effort balancingfilter at each step of a multi-step protocol defends against three attack patterns:first,desertion strategies in which the attacker stops tak-ing part some way through the protocol,having spent less effort in the process than the effort inflicted upon。