单选题 Questions14-17 are based on the passage you have just heard.

单选题 An indigenous tribe in the Peruvian Amazon, the Mashco-Piro, has been trying to make contact with outsiders. In the past, the Mashco-Piro have always resisted interaction with strangers, avoiding—and sometimes killing—any they encounter. Most tribes have had a little, at least indirectly. 'There's always some contact with other isolated tribes, which have contact with other indigenous people, which in turn have contact with the outside world,' says Rebecca Spooner, of Survival International, a London-based organization that advocates for the rights of indigenous peoples. Many of the Amazon tribes choose to avoid contact with outsiders because they have had unpleasant encounters in the past. According to Glenn Shepard, an ethnologist at the Emilio Goeldi Museum in Belem, Brazil, this came after rubber companies massacred tribespeople at the turn of the 20th century. For this reason, some researchers refer to such tribes as 'voluntarily isolated', rather than uncontacted. More recent invasions, especially by miners, oil workers and loggers, may have reinforced the tribes' xenophobia (排外心理). A visiting New Scientist reporter was warned that any unclothed native should be regarded as uncontacted and, thus, very dangerous. In Peru, laws prohibit outsiders from initiating contact with isolated groups in most cases. They also provide protected areas where tribes can live in peace—but there are loopholes (漏洞) that allow oil and mining companies into the region. Brazil has similar laws and policies that allow contact only in life- threatening situations. Anthropologists have an ethical obligation to do no harm to their research subjects, according to the American Anthropological Association's Statement on Ethics. Often, they feel forced out by encroaching (逐渐渗透的) civilization, says Spooner. Survival International has documented some cases where settlements have been bulldozed (推倒) and tribespeople harassed—or even killed. This leaves the survivors feeling like they have no option but to give up. Others see a more benign (和善的) process at work, at least some of the time. 'Tribes may seek contact with outsiders because they begin to trust their intentions,' says Kim Hill, an anthropologist at Arizona State University. 'As soon as the tribes believe they might have some peaceful contact, all these groups want some outside interaction,' he says. 'It's a human trait to want to expand our contacts.' Modern medicine, metal tools and education can also exert a powerful pull. Often, there is a lot of disease because the tribespeople are exposed to novel germs. It is not uncommon for half the population to die of respiratory illness—unless outsiders bring sustained medical care, says Hill. Also, the newly integrated tribespeople frequently end up on the lowest rung of the society they join. Still. he says, when he interviews such people years later, 'I don't find anyone, pretty much, who would want to go back to the old situation.'

单选题For those anxious about committing to a master's degree, there is the post-baccalaureate (学士后) certificate. Usually a four- to seven-course, self-contained certificate provides 25 academic study, or job-specific skills training, with a minimum 26 of time and money, and potentially significant payback. Nearly 51000 people earned the certificate in 2010—a 46 percent increase in five years. For men, having the certificate adds an average 25 percent in earnings; for women, who tend toward less 27 fields such as teaching and health care, the 28 is an average 13 percent, according to research from Georgetown University's Center on Education and the Workforce. About 3 percent of the workforce—or 4 million workers—have certificates. Certificates are market-driven. Colleges and universities, alert to evolving workplace requirements (and business opportunities in higher education), 29 gaps in education and training that appeal to adult students looking for a way to stand out or retool (重新安排) their careers. In some fields, especially health care, education, counseling, engineering and technology, certificates provide compulsory training for certain jobs or promotions, or make one 30 for higher pay scales. In other fields (arts management, interior design, public relations), the certificate shows interest and acquired knowledge in an area that is likely helpful in performing a job. Other certificates reflect 31 in areas so new, or quickly changing, that a demonstrated specialty can put a job applicant in front of the pack: homeland security, sports industry management. Some are purely 32 (African American studies), and some are training-specific (clinical research administration). If you can think of a specialty or job skill you want, there is probably a certificate, and a school-on-ground or online—that will qualify you in the subject. But it is a buyer-beware marketplace, education experts say. A certificate can run into the thousands of dollars (American University's 15-credit online digital media skills certificate costs $12000), so job 33 and schools should be researched before 34 on. A. academic B. boost C. distinguish D. eligible E. identify F. insisting G. investment H. involvement I. limitations J. prospects K. signing L. specialized M. specified N. strengths O. technical

单选题 中国长城(the Great wall)的历史可追溯到公元前5世纪。它建成于公元前5世纪到16世纪之间，目的是保护中国的北部边界。长城是中国历史的一个重要组成部分，对当今中国有着深远的影响。可以说，从某种意义上来看，长城就是历史。大多数人倾向于认为，长城是战争的产物(实际上是防御的产物)，因而其作用理应是和战争紧密相连。但是，情况并非如此。长城存在的大部分时期是和平时期而不是战争年代。大多数时候，长城与文化、外交政策和经济相关。

单选题 Honeybee populations declined by 13.6% over the winter, according to a survey of beekeepers across England. Losses were most severe in the north-east, where the survey recorded a loss rate of 17.1%. Experts worry that the declines will affect plant productivity. There are also concerns that the declines, along with drought conditions in some area, will mean less English honey this year. Martin Smith, president of the British Beekeepers Association, which carried out the survey, said: 'If this was measured against similar losses in livestock, it would be seen as disastrous and there would be great concern on the knock-on impact of food prices.' Beekeepers are puzzled by the decline because the cold winter and early spring should have favoured bees. They stay 'clustered' tightly in their hives when it is cold and dry, saving energy for spring foraging when the temperature rises about 12℃. However, there is good news that the rate of colony loss has slowed. Four years ago, one in three hives was wiped out. Beekeepers suspect that poor nutrition is a likely cause of weakness in adult bees that makes them succumb to diseases spread by a parasitic mite. 'The varroa mite is the number one reason why people lose bees, so the government needs to increase research to cure diseases caused by varroa,' said Smith. 'But a colony that has a good source of pollen and nectar will go into winter more strongly and better able to fend off disease.' The association is calling on everyone who has a garden, small, to plant bee-friendly plants this summer. 'It is really important that there are flowering nectar-rich plants around in August, September and October to provide the nutrition that's needed so the bees can top up their stores of honey in the hive to see them through winter,' said Smith. A campaign being launched next week to save all bees, spearheaded by Sam Roddick and Neal's Yard Remedies, pins the blame for the decline on pesticide. It will start a petition to hand to Downing Street in October to ban the use of a class of pesticides that has been implicated in bee deaths across the world. Roddick said, 'These neonicotinoid pesticides penetrate the plant and indiscriminately attack the nervous system of insects that feed off them, disorientating bees, impairing their foraging ability and weakening their immune system, causing bee Aids. On current evidence, Italy, Germany and Slovenia have banned some varieties. In the UK, it's up to the people to show the government that if there is any doubt that they are contributing to bee deaths, we need to ban them.' A spokesman for the government's National Bee Unit said: 'The UK has a robust system for assessing risks from pesticides and all evidence shows neonicotinoids do not pose an unacceptable risk when products are used correctly, but we will not hesitate to act if presented with any new evidence.'

单选题 Questions6-9 are based on the conversation you have just heard.

单选题 It may seem ridiculous, but in the hunt for sources of alternative energy researchers have come up with fuel cells which are powered by cheese—or at least whey, a by-product in cheese making. Whey is rich in lactose, a sugar which Georgia Antonopoulou, a biochemical engineer at the University of Patras, Greece, says can be consumed by cultures of bacteria contained within a fuel cell to generate an electric current. Microbial fuel cells, as such devices are known, are not a new idea but they are attracting more attention. The organic contents of whey pose an environmental hazard and many governments now impose strict regulations requiring factories to pay for its treatment before disposal. Whey constitutes about 70% of the volume of the milk were used to make cheese. So, just one small feta facility will need to dispose of as such as 4,000 tonnes of whey in a single year, says Dr Antonopoulou. Microbial fuel cells could help, and not just in the cheese-making industry. Breweries, pig farms, food-processing plants and even sewage works could gain from the technology. Traditional fuel cells work by using a catalytic material to oxidize a fuel, such as hydrogen, and make an electric current flow between two electrodes. Microbial fuel cells function in much the same way except that the catalytic reactions are carried out by bacteria contained within the fuel-cell chamber. Under anaerobic conditions (where oxygen is absent), metabolising the fuel by feeding off it and in doing so produce natural chemical reactions that produce a current. In theory microbial fuel cells can run on almost any kind of organic matters, says Chris Melhuish, head of the Bristol Robotics Laboratory, England. 'All you have to do is match the microbial culture with the type of stuff you want to use as fuel,' he says. Dr Melhuish has been trying to power robots on domestic waste-water, but it is tricky. Ideally you would want to use cheap raw-waste products, he says. But traditionally the fuel cells work best with a refined fuel in the form of solutions containing synthetic sugars, such as glucose. However, Dr Antonopoulou has now shown that, using a culture of bacteria obtained from her local waste-water plant, it is possible to get almost as much power from raw whey as from refined fuel, provided the whey is diluted. The trouble is the power output still only amounts to milliwatts, barely enough to trickle-charge a cellphone. And working with raw waste water also presents challenges. Initially Dr Antonopoulou and her colleagues found that the coulombic efficiency of their cells-a measure of how many electrons produced actually flow into a circuit-was particularly low, at around just 2%. This turned out to be because a second set of microbes, within the whey itself, was absorbing them. So, by sterilizing the whey first to kill these other bugs they have now boosted the coulombic efficiency to around 25%.

单选题 Now listen to the following recording and answer questions19-21.

单选题 Space exploration has always been the province of dreamers: The human imagination readily soars where human ingenuity (创造力) struggles to follow. A Voyage to the Moon, often cited as the first science fiction story, was written by Cyrano de Bergerac in 1649. Cyrano was dead and buried for a good three centuries before the first manned rockets started to fly. In 1961, when President Kennedy declared that America would send a man to the moon by the decade's end, those words, too, had a dreamlike quality. They resonated (共鸣) with optimism and ambition in much the same way as the most famous dream speech of all, delivered by Martin Luther King Jr. two years later. By the end of the decade, both visions had yielded concrete results and transformed American society. And yet in many ways the two dreams ended up at odds with each other. The fight for racial and economic equality is intensely pragmatic (讲求实用的) and immediate in its impact. The urge to explore space is just the opposite. It is figuratively and literally otherworldly in its aims. When the dust settled, the space dreamers lost out. There was no grand follow-up to the Apollo missions. The technologically compromised space shuttle program has just come to an end, with no successor. The perpetual argument is that funds are tight, that we have more pressing problems here on Earth. Amid the current concerns about the federal deficit, reaching toward the stars seems a dispensable luxury—as if saving one-thousandth of a single year's budget would solve our problems. But human ingenuity struggles on. NASA is developing a series of robotic probes that will get the most bang from a buck. They will serve as modern Magellans, mapping out the solar system for whatever explorers follow, whether man or machine. On the flip side, companies like Virgin Galactic are plotting a bottom-up assault on the space dream by making it a reality to the public. Private spaceflight could lie within reach of rich civilians in a few years. Another decade or two and it could go mainstream. The space dreamers end up benefiting all of us—not just because of the way they expand human knowledge, or because of the spin-off technologies they produce, but because the two types of dreams feed off each other. Both Martin Luther King and John Kennedy appealed to the idea that humans can transcend what were once considered inherent limitations. Today we face seeming challenges in energy, the environment, health care. Tomorrow we will transcend these as well, and the dreamers will deserve a lot of the credit. The more evidence we collect that our species is capable of greatness, the more we will actually achieve it.

单选题 Questions9-12 are bused on the passage you have just heard.

单选题When my mother's health was failing, I was the 'bad' sister who lived far away and wasn't involved. My sister helped my parents. She never asked me to do anything, and I didn't 27 . I was widowed, raising kids and working, but that wasn't really why I kept to weekly calls and short, infrequent visits. I was 28 in my adolescent role as the aloof (超脱的) achiever, defending myself from my 29 mother and other family craziness. As always, I turned a deaf ear to my sister's criticisms about my not being around more—and I didn't hear her rising desperation. It wasn't until my mom's 30 , watching my dad and sister cling to each other and weep, that I got a hint of their long painful experience—and how badly I'd behaved. My sister was so furious, she 31 spoke to me during my father's last years. To be honest, I'm not a terrible person. So how did I get it so wrong? We hear a lot about the 32 of taking care of our graying population. But the big story beneath the surface is the psychological crisis among middle-aged siblings (兄弟姐妹) who are fighting toward issues involving their aging parents. According to a new survey, an estimated 43.5 million adults in the US are looking after an older 33 or friend. Of these, 43% said they did not feel they had a 34 in this role. And although 7 in 10 said another unpaid caregiver had 35 help in the past year, only 1 in 10 said the burden was split equally. As siblings who are often separated geographically and emotionally, we are having to come together to decide such 36 issues as where Mom and Dad should live and where they should be buried. 'It's like being put down with your siblings in the center of a nuclear reactor and being told, 'Figure it out,' 'says University of Colorado psychologist Sara Honn Quails. A. stuck B. funeral C. provided D. tough E. costs F. volunteer G. relative H. judgmental I. choice J. barely K. flung L. randomly M. noisy N. adapt O. attach