题目内容
Britain's east midlands were once the picture of English countryside, alive with flocks, shepherds, skylarks and buttercups—the stuff of fairytales. In 1941 George Marsh left school at the age of 14 to work as a herdsman in Nottinghamshire, the East Midlands countryside his parents and grandparents farmed. He recalls skylarks nesting in cereal fields, which when accidentally disturbed would fly singing into the sky. But in his lifetime, Marsh has seen the color and diversity of his native land fade. Farmers used to grow about a ton of wheat per acre; now they grow four tons. Pesticides have killed off the insects upon which skylarks fed, and year-round harvesting has driven the birds from their winter nests. Skylarks are now rare. "Farmers kill anything that affects production, "says Marsh." Agriculture is too efficient."
Anecdotal evidence of a looming crisis in biodiversity is now being reinforced by science. In their comprehensive surveys of plants, butterflies and birds over the past 20 to 40 years in Britain, ecologists Jeremy Thomas and Carly Stevens found significant population declines in a third of all native species. Butterflies are the furthest along—71 percent of Britain's 58 species are shrinking in number, and some, like the large blue and tortoiseshell, are already extinct. In Britain's grasslands, a key habitat, 20 percent of all animal, plant and insect species are on the path to extinction. There's hardly a corner of the country's ecology that isn't affected by this downward spiral.
The problem would be bad enough if it were merely local, but it's not: because Britain's temperate ecology is similar to that in so many other parts of the world, It's the best microcosm scientists have been able to study in detail. Scientists have sounded alarms about species' extinction in the past, but always specific to a particular animal or place—whales in the 1980s or the Amazonian rain forests in the 1990s. This time, though, the implications are much wider. The Amazon is a "biodiversity hot spot" with a unique ecology. But in Britain, "the main drivers of change are the same processes responsible for species' declines worldwide, "says Thomas. The findings, published in the journal Science, provide the first clear evidence that the world is in the throes of a massive extinction. Thomas and Stevens argue that we are facing a loss of 65 to 95 percent of the world's species, on the scale of an ice age or the meteorite that may have wiped out the dinosaurs 65 million years ago.
If so, this would be only the sixth time such devastation had occurred in the past 600 million years. The other five were associated with one-off events like the ice ages, a volcanic eruption or a meteor. This time, ecosystems are dying a thousand deaths from over fishing and the razing of the rain forests, but also from advances in agriculture. The British study, for instance, finds that one of the biggest problems is nitrogen pollution Nitrogen is released when fossil fuels burn in cars and power plants, but also when ecologically rich heath-lands are plowed and fertilizers are spread. Nitrogen-rich fertilizers fuel the growth of tall grasses, which in turn overshadow and kill off delicate flowers like harebells and eyebrights.
Even seemingly innocuous practices are responsible for vast ecological damage. When British farmers stopped feeding horses and cattle with hay and switched to silage, a kind of preserved short grass, they eliminated a favorite nesting spot of corncrakes, birds known for their raspy nightly mating calls; corncrake populations have fallen 76 percent in the past 20 years. The depressing list goes on and on.
Many of these practices are being repeated throughout the world, in one form. or another, which is why scientists believe that the British study has global implications. Wildlife is getting blander. "We don't know which species are essential to the web of life so we're taking a massive ri
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Which of the following statements is NOT true of robots？
This astounding industrial accident would not have happened in a world in which robot behavior. was governed by the Three Laws of Robotics drawn up by Isaac Asimov, a science fiction writer. The laws appeared in I, Robot, a book of short stories published in 1950 that inspired a Hollywood film. But decades later the laws, designed to prevent robots from harming people either through action or inaction, remain in the realm of fiction.
With robots now poised to emerge from their industrial cages and to move into homes and workplaces, roboticists are concerned about the safety implications beyond the factory floor. To address these concerns, leading robot experts have come together to try to find ways to prevent robots from harming people. "Security, safety and sex are the big concerns," says Henrik Christensen, chairman of the European Robotics Network at the Swedish Royal Institute of Technology in Stockholm, and one of the organisers of the new roboethics group. Should robots that are strong enough or heavy enough to crush people be allowed into homes？ Should robotic sex dolls resembling children be legally allowed？
These questions may seem esoteric but in the next few years they will become increasingly relevant, says Dr. Christensen. According to the United Nations Economic Commission for Europe's World Robotics Survey, in 2002 the number of domestic and service robots more than tripled, nearly outstripping their industrial counterparts. Japanese industrial firms are racing to build humanoid robots to act as domestic helpers for the elderly, and South Korea has set a goal that 100% of households should have domestic robots by 2020. In light of all this, it is crucial that we start to think about safety and ethical guidelines now, says Dr. Christensen.
So what exactly is being done to protect us from these mechanical menaces？ "Not enough," says Blay Whitby, an artificial-intelligence expert at the University of Sussex in England. This is hardly surprising given that the field of "safety-critical computing" is barely a decade old, he says. But things are changing, and researchers are increasingly taking an interest in trying to make robots safer. One approach, which sounds simple enough, is to try to program them to avoid contact with people altogether. But this is much harder than it sounds. Getting a robot to navigate across a cluttered room is difficult enough without having to take into account what its various limbs or appendages might bump into along the way.
Regulating the behavior. of robots is going to become more difficult in the future, since they will increasingly have self-learning mechanisms built into them, says Gianmarco Veruggio, a roboticist at the Institute of Intelligent Systems for Automation in Genoa, Italy. As a result, their behavior. will become impossible to predict fully, he says, since they will not be behaving in predefined ways but will learn new behavior. as they go.
The word "astounding" in the second paragraph is closest in meaning to
Which of the following is TRUE of the service at a bar？
SECTION B INTERVIEW
Directions: In this section you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. Questions 1 to 5 are based on an interview. At the end of the interview you will be given 10 seconds to answer each of the following five questions.
Now listen to the interview.
听力原文：Tom: Kelvin, could you tell me something about the bars？ I have never been to a bar. You see, Steve, my classmate has invited me to go to a bar tonight.
Kelvin: I see. You know, the word "bar" means a room in a pub. We say the bar when we mean the part of that room where drinks are kept. Soon after you go into the pub, you'll realize that nobody comes to the tables to take orders or money, instead, customers go to the bar to buy their drinks.
Tom: I see. People will go to the bar directly to get their drinks and don't wait for someone to come to take their orders.
Kelvin: That's right. People don't queue at the bar, but they do wait till it's their turn.
Tom: Oh, how do I pay？ I mean do I pay directly after I get the drink or do I have to wait till I am ready to leave like I do in a restaurant？
Kelvin: It's not the custom to pay for all your drinks when you're ready to leave, instead you pay at the bar each time you get drinks. It helps if you're ready to pay as soon as you're served, and you'll notice that many people wait with their money in their hands.
Tom: I see. Do I have to give a tip？
Kelvin: No. It's not the custom to give a tip. It's very common for friends to buy their drinks together in rounds. This means that each person takes a turn to buy drinks for everybody in the group. It's faster and easier, both for you and for the person serving if drinks are bought in this way. Naturally you don't have to have a drink in each round if you don't want one.
Tom: That's interesting.
Kelvin: When you're looking for somewhere to sit, remember that people have to leave their seats to get drinks, etc., so an empty seat may not in fact be available to use. If you're not sure whether a seat is free, ask someone sitting near if. When it's time for another drink, people usually take their glasses back to the bar to be filled again. If you're leaving, the friendly thing to do is to take your glasses back to the bar, thank the person who's been serving you, and say "goodbye" or "goodnight".
Tom: Thank you, Kelvin. This helps me a lot. By the way, what kind of drinks are available in pubs？ Kelvin, Well, you can get both alcoholic and non-alcoholic. Besides alcoholic drinks such as beer and wine, there is cider, which is made from apples, usually sold in bottles, port—a type of thick, sweet wine from Portugal, sherry, which is a type of wine from Spain, and spirits—these are a kind of strong alcoholic drinks such as whisky and brandy.
Tom: What about non-alcoholic？ I don't drink alcohol.
Kelvin: Well, they offer all kinds of fruit juices, such as orange and tomato. These drinks are usually sold in small bottles. And soft drinks,' we often call sweet drinks, like Coke and Fanta. They are normally sold in small bottles or cans. And lemonade, which is a clear and sweet drink made with carbonated water. They also serve cordials.
Tom: What are cordials？
Kelvin: Cordials are strong and sweet drinks tasting of fruit, such as lime cordial, black-currant cordial. ;I'hey are often added to other drinks or drunk with water.
Tom: I don't like sweet drinks. Are there any other non-alcoholic drinks？
Kelvin: Yes, mineral water, but it's not available in all pubs.
Tom: Kelvin, one more question. What is VAT？ I saw this on most goods in Britain？
Kelvin: Well, VAT stands for Value Added Tax. The price shown on most goods in Britain includes a tax of 15%. If you use the Retail Export Scheme this tax can be returned to you if you take the goods with you when you leave Britain. You may have to spend a certain sum of money before you qualify for the scheme, and you
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