单选题Questions 23～26

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单选题 I have just come home after viewing some astonishing works of art that were recently discovered in Church Hole cave in Nottinghamshire. They are not drawings, as one would expect, but etchings, and they depict a huge range of wild animals. The artists who created them lived around 13,000 years ago, and the images are remarkable on a variety of counts. First of all, their sheer number is staggering. There are ninety all together. Moreover, fifty-eight of them are on the ceiling. This is extremely rare in cave art, according to a leading expert, Dr. Wilbur Samson of Central Midlands University. "Wall pictures are the norm," he says. "But more importantly, the Church Hole etchings are an incredible artistic achievement. They can hold their own in comparison with the best found in continental Europe." I am not a student of the subject, so I have to take his word for it. However, you do not have to be an expert to appreciate their beauty. In fact, it is the wider significance of the etchings that is likely to attract most attention in academic circles, since they radically alter our view of life in Britain during this epoch. It had previously been thought that ice-age hunters in this country were isolated from people in more central areas of Europe, but the Church Hole images prove that ancient Britons were part of a culture that had spread right across the continent. And they were at least as sophisticated culturally as their counterparts on the mainland. An initial survey of the site last year failed to reveal the presence of the etchings. The reason lies in the expectations of the researchers. They had been looking for the usual type of cave drawing or painting, which shows up best under direct light. Consequently, they used powerful torches, shining them straight onto the rock face. However, the Church Hole images are modifications of the rock itself, and show up best when seen from a certain angle in the natural light of early morning. Having been fortunate to see them at this hour, I can only say that I was deeply and unexpectedly moved. While most cave art often seems to have been created in a shadowy past very remote from us, these somehow, convey the impression that they were made yesterday. Dr. Samson feels that the lighting factor provides important information about the likely function of these works of art. "I think the artists knew very well that the etchings would hardly be visible except early in the morning. We can therefore deduce that the chamber was used for rituals involving animal worship, and that they were conducted just after dawn as a preliminary to the day's hunting." To which I can only add that I felt deeply privileged to have been able to view Church Hole. It is a site of tremendous importance culturally and is part of the heritage, not only of this country, but the world as a whole.

单选题 Without regular supplies of some hormones our capacity to behave would be seriously impaired; without others we would soon die. Tiny amounts of some hormones can modify moods and actions, our inclination to eat or drink, our aggressiveness or submissiveness, and our reproductive and parental behavior. And hormones do more than influence adult behavior; early in life they help to determine the development of bodily form and may even determine an individual's behavioral capacities. Later in life the changing outputs of some endocrine glands and the body's changing sensitivity to some hormones are essential aspects of the phenomena of aging. Communication within the body and the consequent integration of behavior were considered the exclusive province of the nervous system up to the beginning of the present century. The emergence of endocrinology as a separate discipline can probably be traced to the experiments of Bayliss and Starling on the hormone secretion. This substance is secreted from cells in the intestinal walls when food enters the stomach; it travels through the bloodstream and stimulates the pancreas to liberate pancreatic juice, which aids in digestion. By showing that special cells secrete chemical agents that are conveyed by the bloodstream and regulate distant target organs or tissues. Bayliss and Starling demonstrated that chemical integration could occur without participation of the nervous system. The term "hormone" was first used with reference to secretion. Starling derived the term from the Greek hormone, meaning "to excite or set in motion". The term "endocrine" was introduced shortly thereafter. "Endocrine" is used to refer to glands that secrete products into the bloodstream. The term "endocrine" contrasts with "exocrine", which is applied to glands that secrete their products though ducts to the site of action. Examples of exocrine glands are the tear glands, the sweat glands, and the pancreas, which secrete pancreatic juice through a duct into the intestine. Exocrine glands are also called duct glands, while endocrine glands are called ductless glands.

单选题No matter if you"re leafing through those glossy admissions brochures, attending an information session on campus or browsing a college fair with your teen, there"s always one big thought at the back of the mind of every parent: Wait, how much is this college degree going to cost me? Thankfully, there are some new tools out there to make figuring out costs a little easier. This September the Department of Education released its College Scorecard, a project designed to help parents and students make more informed decisions about higher education. The tool provides information on college costs, graduation rates, average starting salaries, post-graduation and information that can help people pick the best school for their financial and academic needs. With the College Scorecard, you see a breakdown of what you"d actually pay for a college education, based on your family"s income. This is the most important aspect of this tool, because while the "sticker price" of a school may be high, you most likely won"t pay full price to go there. For example, although Harvard"s list price is around $60,000 according to its admissions website, the average family will pay just over $14,000 per year once you factor in grants and financial aid. The tool lets you compare schools" stats side by side, including their financial information. In the search function, you can filter out what kind of degree you want (two-year or four-year), location, public or private, size, major or program and more to make a really specific comparison. If any schools catch your eye, you can click on "View More Details" for a comprehensive summary (SAT/ACT scores to get in, what typical student debt is like, etc.). You can also search for a specific school to get all the stats you want on it. You can also check out NPR"s college cost calculator, which uses the College Scorecard raw data of 150 major colleges and universities to show you right off the bat the net price (price of college minus financial aid, grants and scholarships) for various incomes compared to that scary sticker price. It"s a quick but less detailed summary looking specifically at costs. While these tools can"t determine the exact dollar amount you"ll have to pay, they do give you a better ballpark estimate of what college costs you are expected to be able to pay. Knowing that now will help you decide what school makes the best financial sense for your family.

单选题Most growing plants contain much more water than all other materials combined. C. R. Barnes has suggested that it is as proper to term the plant a water structure as to call a house composed mainly of brick a brick building. Certain it is that all essential processes of plant growth and development occur in water. The mineral elements from the soil that are usable by the plant must be dissolved in the soil solution before they can be taken into the root. They are carried to all parts of the growing plant and are built into essential plant materials while in a dissolved state. The carbon dioxide from the air may enter the leaf as a gas but is dissolved in water in the leaf before it is combined with a part of the water to form simple sugars—the base material from which the plant body is mainly built. Actively growing plant parts are generally 75 to 90 percent water. Structural parts of plants, such as woody stems no longer actively growing, may have much less water than growing tissues. The actual amount of water in the plant at any one time, however, is only a very small part of what passes through it during its development. The processes of photosynthesis, by which carbon dioxide and water are combined-in the presence of chlorophyll and with energy derived from light-to form sugars, require that carbon dioxide from the air enter the plant. This occurs mainly in the leaves. The leaf surface is not solid but contains great numbers of minute openings, through which the carbon dioxide enters. The same structure that permits the one gas to enter the leaf, however, permits another gas—water vapor—to be lost from it. Since carbon dioxide is present in the air only in trace quantities (3 to 4 parts in 10,000 parts of air) and water vapor is near saturation in the air spaces within the leaf (at 80°F, saturated air would contain about 186 parts of water vapor in 10,000 parts of air), the total amount of water vapor lost is many times the carbon dioxide intake. Actually, because of wind and other factors, the loss of water in proportion to carbon dioxide intake may be even greater than the relative concentrations of the two gases. Also, not all of the carbon dioxide that enters the leaf is synthesized into carbohydrates.

单选题Britain, somewhat proudly, has been crowned the most watched society in the world. The country boasts 4.2 million security cameras (one for every 14 people) , a number expected to double in the next decade. A typical Londoner makes an estimated 300 closed-circuit television (CCTV) appearances a day, according to the British nonprofit surveillance Studies Network, an average easily met in the short walk between Trafalgar Square and the Houses of Parliament. Public opinion on this state of affairs is generally positive, according to recent polls. And how useful is CCTV in busting bad guys? Not much, according to Scotland Yard. In terms of cost benefit, the enormous expenditure has done very little in actually preventing and solving crime. Right under Big Brother- s nose, a new class of guerrilla artists and hackers are comrnandeering the boring, grainy images of vacant parking lots and empty corridors for their own purposes. For about $ 80 at any electronics supply store and some technical know-how, it is possible to tap into London's CCTV hotspots with a simple wireless receiver (sold with any home-security camera) and a battery to power it. Dubbed "video sniffing," the pastime evolved out of the days before broadband became widely available, when "war-chalkers" scouted the city for unsecured Wi-Fi networks and marked them with chalk using special symbols. Sniffing is catching on in other parts of Europe, spread by a small but globally connected community of practitioners. "It's actually a really relaxing thing to do on a Sunday," says Joao Wilbert, a master's student in interactive media, who slowly paces the streets in London like a treasure hunter, carefully watching a tiny handheld monitor for something to flicker onto the screen. The excursions pick up obscure, random shots from the upper corners of restaurants and hotel lobbies, or of a young couple shopping in a house wares department nearby. Eerily, baby cribs are the most common images. Wireless child monitors work on the same frequency as other surveillance systems, and are almost never encrypted or secured. Given that sniffing is illegal, some artists have found another way to obtain security footage: they ask for it, in a letter along with a check for ￡10. In making her film "Faceless," Austrian- born artist Manu Luksch made use of a little-known law, included within Britain- s Data Protection Act, requiring CCTV operators to release a copy of their footage upon the request of anyone captured on their cameras. "Within the maximum period of 40 days I received some recordings in my mail," says Luksch. "And I thought, Wow, that works well. Why not make a feature length, science-fiction love story?" After four years of performing, staging large dance ensembles in public atriums and submitting the proper paperwork, Luksch produced a haunting, beautifully choreographed film and social commentary, in which the operators have blocked out each and every performer's face, in compliance with Britain- s privacy laws. "The Duelists," one of the more well known CCTV movies, was shot by filmmaker David Valentine entirely with the security cameras in a mall in Manchester. He was able to cajole his way into the control booth for the project, but he is also credited with having advanced video sniffing to an art form and social tool. He's collaborated with MediaShed, an organization based in Southend- on-Sea just outside London that works with homeless youth, using sniffing as a way to gain their interest and re-engage them with society. In some cases video sniffing has morphed into a form of hacking, in which the sniffer does more than just watch. Using a transmitter strong enough to override the frequency that most cameras use, sniffers can hijack wireless networks and broadcast different images back to the security desk. Most sniffers, hijackers and artists using CCTV are critical of the present level of surveillance, but they' re also interested in establishing a dialogue about what is typically a secretive arrangement. The ability to tap into wireless surveillance systems and take them over points out a flaw in the elaborate security apparatus that has evolved around us. As anthropologists tell us. the act of observation changes what's being observed. Cameras "reorder the environment," says Graham Harwood, artistic director of the group Mongrel, which specializes in digital media. That's especially true of saturated London. Like "flash mobs" and "wifipicning," both large, spontaneous gatherings of people centered around communications technology, sniffing and hijacking could become the next high-tech social phenomenon. Of course, it will likely disappear quickly once the surveillance industry catches on to the shenanigans and beefs up its security. But the cameras will remain*

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单选题A visitor from Barcelona arrives at a Madrid government office in mid-afternoon. And is surprised to find only the cleaning lady there. "Don"t they work in the afternoons?" he asks. "No," she replies, "They don"t work in the mornings. In the afternoons they don"t come." Lazy Madrid, busy Barcelona: it is just one of many stereotypes about Spain"s great rivals. Mostly, the stereotypes are born of Barcelona"s bitterness at its second-class status. Barcelona is the capital of Catalonia, a proudly autonomous region, but Madrid is the capital of Spain. This causes resentment. It makes Barcelona the largest city in Western Europe not to be a national, capital. Worse, Barcelona (Catalonia"s capital since the ninth century) regards Madrid (a creation of Philip Ⅱ in the 16th century) as an upstart. And, after being bossed about for so long, who can blame them? Over the years governments in Madrid did their best to strip Barcelona of political power. They tried to squash the Catalan Language. They even decided what the modern city should look like: in 1860 an order from Madrid overruled Barcelona"s choice of plan for its big expansion, and opted for a grid layout. Barcelona has the liberalism that often characterizes port cities. As Catalans see is. While Madrid bathes in bureaucracy, Barcelona gets on with business. Anold-fashioned seriousness in Madrid, isolated high up on Spain"s central plateau, contrasts with the light-heartedness of Barcelona, open to Europe and aggressively avant-garde. Upon to a point, these old caricatures still hold true. No visitor to government buildings in the two cities can fail to be struck by the contrast between them. In Madrid, there are creaky wooden floor, antique furniture and walls covered with paintings by Spanish old masters. In Barcelona, the city of Gaudi and Miro, designer chairs and tables are evidence of the place"s obsession with modernism. Meetings of the Catalan cabinet are held in room with a large, modern painting by Antoni Tapies. And yet, these days, the similarities between two cities are at least striking as the contrasts. Madrid is hardly lazy any more. Visitors find it hard to keep up with the pace of the place. Nor is it old-fashioned. Indeed, it has become almost outrageously modern. To judge by the local cuisine, you would think the place was a port. although far from the sea, seafood is a miraculous Madrid specialty. As banks and business have been drawn to Madrid and industrial centre as an administrative one, Barcelona, meanwhile, in Spain"s traditional industrial heartland, has been experiencing a rise in bureaucracy. The rivalry between Madrid and Barcelona is bound to remain fierce, not least on the soccer field, where Real Madrid and Barcelona compete for Spanish supremacy. Barcelona will continue to press for yet more power to be devolved to it from Madrid: it is calling for the Senate, Spain"s upper house of parliament, to be moved to the Catalan capital. But with a lot of local autonomy restored, and with the success of the 1992 Olympics behind it, the chip on Barcelona"s shoulder is becoming ever harder to detect.

单选题 {{B}}Questions 15-18{{/B}}

单选题Questions 11-14

单选题Like the space telescope he championed, astronomer Lyman Spitzer faced some perilous moments in his career. Most notably, on a July day in 1945, he happened to be in the Empire State building when a B- 25 Mitchell bomber lost its way in fog and crashed into the skyscraper 14 floors above him. Seeing debris falling past the window, his curiosity got the better of him, as Robert Zimmerman recounts in his Hubble history, The Universe in a Mirror. Spitzer tried to poke his head out the window to see what was going on, but others quickly convinced him it was too dangerous. Spitzer was not the first astronomer to dream of sending a telescope above the distorting effects of the atmosphere, but it was his tireless advocacy, in part, that led NASA to launch the Hubble Space Telescope in 1990. Initially jubilant, astronomers were soon horrified to discover that Hubble's 2.4-metre main mirror had been ground to the wrong shape. Although it was only off by 2.2 micrometers, this badly blurred the teleseope's vision and made the scientists who had promised the world new images and science in exchange for $1.5 billion of public money the butt of jokes. The fiasco, inevitably dubbed "Hubble Trouble" by the press, wasn't helped when even the limited science the crippled Hubble could do was threatened as its gyroscopes, needed to control the orientation of the telescope, started to fail one by one. By 1993, as NASA prepared to launch a rescue mission, the situation looked bleak. The telescope "probably wouldn't have gone on for more than a year or two" without repairs, says John Grunsfeld, an astronaut who flew on the most recent Hubble servicing mission. Happily, the rescue mission was a success. Shuttle astronauts installed new instruments that corrected for the flawed mirror, and replaced the gyroscopes. Two years later, Hubble gave us the deepest ever view of the universe, peering back to an era just 1 billion years after the big bang to see the primordial building blocks that aggregated to form galaxies like our own. The success of the 1993 servicing mission encouraged NASA to mount three more (in 1997, 1999 and 2002). Far from merely keeping the observatory alive, astronauts installed updated instruments on these missions that dramatically improved Hubble's power. It was "as if you took in your Chevy Nova [for repairs] and they gave you back a Lear jet," says Steven Beckwith, who from 1998 to 2005 headed the Space Telescope Science Institute (STScI) in Baltimore, Maryland, where Hubble's observations are planned. Along the way, in 1998, Hubble's measurements of supernovas in distant galaxies unexpectedly revealed that the universe is expanding at an ever-increasing pace, propelled by a mysterious entity now known as dark energy. In 2001 the space observatory also managed to make the first measurement of a chemical in the atmosphere of a planet in an alien solar system. Despite its successes, Hubble's life looked like it would be cut short when in 2004, NASA's then administrator Scan O'Keefe announced the agency would send no more servicing missions to Hubble, citing unacceptable risks to astronauts in the wake of the Columbia shuttle disaster of 2003, in which the craft exploded on reentry, killing its crew. By this time, three of Hubble's gyroscopes were already broken or ailing and no one was sure how long the other three would last. Citizen petitions and an outcry among astronomers put pressure on NASA, and after a high-level panel of experts declared that another mission to Hubble would not be exceptionally risky, the agency reversed course, leading to the most recent servicing mission, in May 2009. No more are planned. The remainder of the shuttle fleet that astronauts used to reach Hubble is scheduled to retire by the year's end. And in 2014, NASA plans to launch Hubble's successor, an infrared observatory called the James Webb Space Telescope, which will probe galaxies even further away and make more measurements of exoplanet atmospheres. According to Grunsfeld, now STScl's deputy director, plans are afoot for a robotic mission to grab Hubble when it reaches the end of its useful life, nudging it into Earth's atmosphere where most of it would be incinerated. Only the mirror is sturdy enough to survive the fall into an empty patch of ocean. But let's not get ahead of ourselves--Hubble is far from finished. The instruments installed in May 2009, including the Wide Field Camera 3, which took this image of the Butterfly nebula, 3800 light years away, have boosted its powers yet again. It might have as much as a decade of life left even without more servicing. "It really is only reaching its full stride now, after 20 years," says Grunsfeld. A key priority for Hubble will be to explore the origin of dark energy by probing for it at earlier times in the universe's history. Hubble scientist Malcolm Niedner of NASA's Goddard Space Flight Center in Greenbelt, Maryland, is not willing to bet on what its most important discovery will be. "More than half of the most amazing textbook-changing science to emerge from this telescope occurred in areas we couldn't even have dreamed of," he says. "Expect the unexpected. /

单选题 An experimental treatment for Parkinson's disease seemed to improve symptoms—dramatically so, for one 59-year-old man—without causing side effects in an early study of a dozen patients. The gene therapy treatment involved slipping billions of copies of a gene into the brain to calm overactive brain circuitry. More than half a million Americans have Parkinson's. They endure symptoms that include tremors, rigidity in their limbs, slowness of movement and impaired balance and coordination. Eventually they can become severely disabled. The small study focused on testing the safety of the procedure rather than its effectiveness, and experts cautioned it's too soon to draw conclusions about how well it works. But they called the results promising and said the approach merits further studies. "We still have quite a bit more testing to do," said Dr. Michael Kaplitt of Weill Cornell Medical College in New York, an author of the study. Still, "the initial results are extremely encouraging". Nathan Klein, a 59-year-old freelance television producer in Port Washington, N.Y., said the disease left him "pretty messed up". It weakened his voice, impaired his walking and made his hand tremble so badly he couldn't hold a glass of wine without spilling it all. Klein was the first patient to be treated with Kaplitt's gene therapy procedure in 2003, and he said his symptoms gradually subsided afterward. Nowadays, he said, apart from freezing now and then when he wants to walk, the symptoms are basically gone. "I'm elated," said Klein, who continues to take his regular pills for the disease. "It's unbelievable." Kaplitt, who has a financial interest in Neurologix Inc., which paid for the research, noted that the 12 patients in the study still have Parkinson's symptoms. The amount of medication they were already taking for their symptoms didn't change significantly in the year after the surgery. Current medicines can control symptoms, but can't stop the disease from getting worse over time, and they can produce troublesome side effects like uncontrollable movement. Some patients gain relief from a surgical treatment called deep brain stimulation, in which electrodes are placed in the brain and connected to a programmable stimulator. Kaplitt's procedure was aimed at achieving the same goal as that surgery, calming overactive circuitry in the brain. It gets overactive because it loses the normal supply of a chemical called GABA. The gene therapy was designed to make the brain produce more GABA. For the gene therapy surgery, a tube about the width of a hair was threaded through a hole about the size of a quarter at the top of the skull. The tube delivered a dose of a virus engineered to ferry copies of a gene into cells of a brain region called the subthalamic nucleus. The gene copies enable the cells to pump out more GABA.

单选题______the temperature going down so quickly, I don't think we are able to go on with our experiment. [A] For [B] By [C] From [D] With

单选题 Questions 19-22

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单选题Questions 6 to 10 are based on the following talk.

单选题 Questions 16-20 Can electricity cause cancer? In a society that literally runs on electric power, the very idea seems preposterous. But for more than a decade, a growing band of scientists and journalists has pointed to studies that seem to link exposure to electromagnetic fields with increased risk of leukemia and other malignancies. The implications are unsettling, to say the least, since everyone comes into contact with such fields, which are generated by everything electrical, from power lines and antennas to personal computers and micro-wave ovens. Because evidence on the subject is inconclusive and often contradictory, it has been hard to decide whether concern about the health effects of electricity is legitimate or the worst kind of paranoia. Now the alarmists have gained some qualified support from the U. S. Environmental Protection Agency. In the executive summary of a new scientific review, released in draft form late last week, the EPA has put forward what amounts to the most serious government warning to date. The agency tentatively concludes that scientific evidence "suggests a causal link" between extremely low- frequency electromagnetic fields those having very longwave-lengths--and leukemia, lymphoma and brain cancer. While the report falls short of classifying ELF fields as probable carcinogens, it does identify the common 60-hertz magnetic field as "a possible, but not proven, cause of cancer in humans. " The report is no reason to panic--or even to lose sleep. If there is a cancer risk, it is a small one. The evidence is still so controversial that the draft stirred a great deal of debate within the Bush Administration, and the EPA released it over strong objections from the Pentagon and the White House. But now no one can deny that the issue must be taken seriously and that much more research is needed. At the heart of the debate is a simple and well-understood physical phenomenon: When an electric current passes through a wire, it generates an electromagnetic field that exerts forces on surrounding objects. For many years, scientists dismissed any suggestion that such forces might be harmful, primarily because they are so extraordinarily weak. The ELF magnetic field generated by a video terminal measures only a few milligauss, or about one-hundredth the strength of the earth's own magnetic field. The electric fields surrounding a power line can be as high as 10 kilovolts per meter, but the corresponding field induced in human cells will be only about 1 millivolt per meter. This is far less than the electric fields that the cells themselves generate. How could such minuscule forces pose a health danger? The consensus used to be that they could not, and for decades scientists concentrated on more powerful kinds of radiation, like X-rays, that pack sufficient wallop to knock electrons out of the molecules that make up the human body. Such "ionizing" radiations have been clearly linked to increased cancer risks and there are regulations to control emissions. But epidemiological studies, which find statistical associations between sets of data, do not prove cause and effect. Though there is a body of laboratory work showing that exposure to ELF fields can have biological effects on animal tissues, a mechanism by which those effects could lead to cancerous growths has never been found. The Pentagon is far from persuaded. In a blistering 33-page critique of the EPA report, Air Force scientists charge its authors with having "biased the entire document" toward proving a link. "Our reviewers are convinced that there is no suggestion that (electromagnetic fields) present in the environment induce or promote cancer," the Air Force concludes. "It is astonishing that the EPA would lend its imprimatur on this report. " Then Pentagon's concern is understandable. There is hardly a unit of the modern military that does not depend on the heavy use of some kind of electronic equipment, from huge ground-based radar towers to the defense systems built into every warship and plane.

单选题Questions 16-20 California is a land of variety and contrast. Almost every type of physical land feature, sort of arctic ice fields and tropical jungles can be found within its borders. Sharply contrasting types of land often lie very close to one another. People living in Bakersfield, for instance, can visit the Pacific Ocean and the coastal plain, the fertile San Joaquin Valley, the arid Mojave Desert, and the high Sierra Nevada, all within a radius of about 100 miles. In other areas it is possible to go snow skiing in the morning and surfing in the evening of the same day, without having to travel long distance. Contrast abounds in California. The highest point in the United States (outside Alaska) is in California, and so is the lowest point (including Alaska). Mount Whitney, 14,494 feet above sea level, is separated from Death Valley, 282 feet below sea level, by a distance of only 100 miles. The two areas have a difference in altitude of almost three miles. California has deep, clear mountain lakes like Lake Tahoe, the deepest in the country, but it also has shallow, salty desert lakes. It has Lake Tulainyo, 12,020 feet above sea level, and the lowest lake in the country, the Salton Sea, 236 feet below sea level Some of its lakes, like Owens Lake in Death Valley, are not lakes at all.. they are dried-up lake beds. In addition to mountains, lakes, valleys, deserts, and plateaus, California has its Pacific coastline, stretching longer than the coastlines of Oregon and Washington combined.