单选题People have been painting pictures for at least 30,000 years. The earliest pictures were painted by people who hunted animals. They used to paint pictures of the animals they wanted to catch and kill. Pictures of this kind have been found on the walls of caves in France and Spain. No one knows -why they Were painted there. Perhaps the painters thought that their pictures would help them to catch these animals. Or perhaps human beings have always wanted to tell stories in pictures. About 5000 years ago, the Egyptians and other people in the Near East began to use pictures as kind of writing. They drew simple pictures or signs to represent things and ideas, and also to represent the sounds of their language. The signs there people used became a kind of alphabet. The Egyptians used to record information and to tell stories by putting picture-writing and pictures together. When an important person died, scenes and stories from his life were painted and carved on the walls of the place where he was buried. Some of these pictures are like modem comic strip stories. It has been said that Egypt is the home of the comic strip. But for Egyptians, pictures still had magic power. So they did not try to make their way of writing simple. The ordinary people could not understand it. By the year 1000 BC, people who lived in the area around the Mediterranean Sea had developed a simpler system of writing. The signs they used were very easy to write, and there were fewer of them than in the Egyptian system. This was because each sign, or letter, represented only one sound in their language. The Greeks developed this system and formed the letters of the Greek alphabet. The Romans copied the idea and the Roman alphebet is now used all over the world. These days, we can write down a story, or record information, without using pictures. But we still need pictures of all kinds: drawing, photographs, signs and diagrams. We find them everywhere: in books and newspapers, in the street, and on the wails of the places where we live and work. Pictures help us to understand and remember things more easily, and they can make a story much more interesting.

单选题A Biological Clock Every living thing has what scientists call a biological clock that controls behavior. The biological clock tells 1 when to form flowers and when the flowers should open. It tells 2 when to leave the protective cocoons and fly away, and it tells animals and human beings when to eat, sleep and wake. Events outside the plant and animal 3 the actions of some biological clocks. Scientists recently found, for example, that a tiny animal changes the color of its fur 4 the number of hours of daylight. In the short 5 of winter, its fur becomes white. The fur becomes gray brown in color in the longer hours of daylight in summer. Inner signals control other biological clocks. German scientists found that some kind of internal clock seems to order birds to begin their long migration 6 twice each year. Birds 7 flying become restless when it is time for the trip, 8 they become calm again when the time of the flight has ended. Scientists say they are beginning to learn which 9 of the brain contain biological clocks. An American researcher, Martin Moorhead, said a small group of cells near the front of the brain 10 to control the timing of some of our actions. These 11 tell a person when to 12 , when to sleep and when to seek food. Scientists say there probably are other biological clock cells that control other body activities. Dr. Moorhead is studying 13 our biological clocks affect the way we do our work. For example, most of us have great difficulty if we must often change to different work hours. 14 can take many days for a human body to accept the major change in work hours. Dr. Moorhead said industrial officials should have a better understanding of biological clocks and how they affect workers. He said 15 understanding could cut sickness and accidents at work and would help increase a factory"s production.

单选题The mail I wrote to my mom was delivered this morning.

单选题Technological Utopia for Developing Countries Cyberspace (网络空间), data superhighways, multimedia for those who have seen the future, the linking of computers, television and telephones will change our lives forever. Yet for all the talk of a forthcoming technological Utopia (乌托邦) ,little attention has been given to the implications of these developments for the poor. As with all new high technology, while the West concerns itself with the "how", the question of "for whom" is put aside once again. Economists are only now realizing the full extent to which the communications revolution has affected the world economy. Information technology allows the extension of trade across geographical and industrial boundaries, and transnational corporations take full advantage of it. Terms of trade exchange, interest rates and money movements are more important than the production of goods. The electronic economy made possible by information technology allows the haves to increase their control on global markets with destructive impact on the have-nots. For them the result is instability. Developing countries which rely on the production of a small range of goods for export are made to feel like small parts in the international economic machine. As "futures" (期货) are traded on computer screens, developing countries simply have less and less control of their destinies. So what are the options for regaining control? One alternative is for developing countries to buy in the latest computers and telecommunications themselves—so-called "development communications" modernization. Yet this leads to long-term dependency and perhaps permanent constraints on developing countries" economies. Communications technology is generally exported from the U.S., Europe or Japan; the patents, skills and ability to manufacture remain in the hands of a few industrialized countries. It is also expensive, and imported products and services must therefore be bought on credit—credit usually provided by the very countries whose companies stand to gain. Furthermore, when new technology is introduced there is often too low a level of expertise to exploit it for native development. This means that while local elites, foreign communities and subsidiaries of transnational corporations may benefit, but not developing countries.

单选题For years, U. S. automakers have fought tougher regulations by arguing that Americans tend to prefer larger, gas-guzzling SUVs and trucks. That's not always true: when gas prices were at an all-time high last summer, sales of SUVs were down considerably, while hybrids flew off dealer lots. Since then, prices at the pump have dropped-and so has the appetite for small cars. As long as the price of gas remains volatile(易变的, 动荡不定的), it's far from certain that Americans will buy the more efficient cars and trucks the new standards will require automakers to produce. In the long run, though, a gas tax that puts a floor on fuel prices may be the only way to break America's SUV addiction. But Obama has said he's not interested. "You need a price signal. Regulations alone won't do it," says Lester Lave, director of the Carnegie Mellon Green Design Initiative. Americans' appetite for SUVs dropped whenA. gas prices hit new high last summer.B. hybrids were out of stock last summer.C. the government set limits on fuel price last summer.D. the gas price remained fluctuing last summer.

单选题Jack was dismissed .

单选题You have to make sure that you have chosen a secure solution.A. clearB. secretC. advisableD. safe

单选题The food we have is inadequate .

单选题Paper or Plastic? Take a walk along the Chesapeake Bay, and you are likely to see plastic bags floating in the water. Ever since these now ubiquitous symbols of American super-consumption showed up in the supermarkets, plastic shopping bags have made their 1 into local waterways, and from there, into the bay, where they can 2 wildlife. Piles of them—the 3 takes centuries to decompose—show up in landfills and on city streets. Plastic bags also take an environmental toll in the form of millions of barrels of oil expended every year to produce them. Enter Annapolis 4 you will see plastic bags distributed free in department stores and supermarkets. Alderman Sam Shropshire has introduced a well-meaning proposal to ban retailers 5 distributing plastic shopping bags in Maryland"s capital. Instead, retailers would be required to offer bags 6 recycled paper and to sell reusable bags. The city of Baltimore is considering a similar measure. Opponents of the idea, however, argue that 7 bags are harmful, too: they cost more to make, they consume more 8 to transport, and recycling them causes more pollution than recycling plastic. The argument for depriving Annapolis residents of their plastic bags is 9 accepted. Everyone in this 10 is right about one thing: disposable shopping bags of any type are 11 , and the best outcome would be for customers to reuse bags instead. Annapolis"s mayor is investigating how to hand out free, reusable shopping bags to city residents, a proposal that can proceed regardless of whether other bags are banned. A less-expensive 12 would be to encourage retailers to give discounts to customers 13 bring their own reusable bags, a policy that a spokesman for the supermarket Giant Food says its chain already has in place. And this policy would be more 14 if stores imitated furniture mega-retailer Ikea and charged for disposable bags at the checkout counter. A broad ban on the use of plastic shopping bags, which would merely replace some forms of pollution with others, is not the 15 .

单选题下面有3篇短文，每篇短文后有5道题，每题后面有4个选项。请仔细阅读短文并根据短文回答其后面的问题，从4个选项中选择1个最佳答案。{{B}}第一篇{{/B}} {{B}}Invisibility Ring{{/B}} Scientists can't yet make an invisibility cloak like the one that Harry Potter uses. But, for the first time, they've constructed a simple cloaking device that makes itself and something placed inside it invisible to microwaves. When a person "sees" an object, his or her eye senses many different waves of visible light as they bounce off the object. The eye and brain then work together to organize these sensations and reconstruct the object's original shape. So, to make an object invisible, scientists have to keep waves from bouncing off it. And they have to make sure the object casts no shadow. Otherwise, the absence of reflected light on one side would give the object away. Invisibility isn't possible yet with waves of light that the human eye can see. But it is now possible with microwaves. Like visible light, microwaves are a form of radiant energy. They are part of the electromagnetic spectrum, which also includes radio waves, infrared light, ultraviolet rays, X rays, and gamma rays. The wavelengths of microwaves are shorter than those of radio waves but longer than those of visible light. The scientists' new "invisibility device" is the size of a drink coaster and shaped like a ring. The ring is made of a special material with unusual ability. When microwaves strike the ring, very few bounce off it. Instead, they pass through the ring, which bends the waves all the way around until they reach the opposite side. The waves then return to their original paths. To a detector set up to receive microwaves on the other side of the ring, it looks as if the waves never changed their paths -- as if there were no object in the way ! So, the ring is effectively invisible. When the researchers put a small copper loop inside the ring, it, too, is nearly invisible. However, the cloaking device and anything inside it do cast a pale shadow. And the device works only for microwaves, not for visible light or any kind of electromagnetic radiation. So, Harry Potter's invisibility cloak doesn't have any real competition yet.

单选题{{B}}第三篇{{/B}} {{B}} Controlling Robots with the Mind{{/B}} Belle, our tiny monkey, was seated in her special chair inside a chamber at our Duke University lab. Her right hand grasped a joystick (操纵杆) as she watched a horizontal series of lights on a display panel. She knew that if a light suddenly shone and she moved the joystick left or right to correspond to its position, she would be sent a drop of fruit juice into her mouth. Belle wore a cap glued to her head. Under it were four plastic connectors, which fed arrays of microwires - each wire finer than the finest sewing thread- into different regions of Belle's motor cortex (脑皮层), the brain tissue that plans movements and sends instructions. Each of the 100 microwires lay beside a single motor neuron (神经元). When a neuron produced an electrical discharge, the adjacent microwire would capture the currant and send it up through a small wiring bundle that ran from Belle's cap to a box of electronics on a table next to the booth. The box, in turn, was linked to two computers, one next door and the other half a country away. After months of hard work, we were about to test the idea that we could reliably translate the raw electrical activity in a living being's brain - Belle's mere thoughts - into signals that could direct the actions of a robot. We had assembled a multijointed robot arm in this room, away from Belle's view, which she would control for the first time. As soon as Belle's brain sensed a lit spot on the panel, electronics in the box running two real-time mathematical models would rapidly analyze the tiny action potentials produced by her brain cells. Our lab computer would convert the electrical patterns into instructions that would direct the robot arm. Six hundred miles north, in Cambridge, Mass, a different computer would produce the same actions in another robot arm built by Mandayam A. Srinivasan. If we had done everything correctly, the two robot arms would behave as Belle's arm did, at exactly the same time. Finally the moment came. We randomly switched on lights in front of Belle, and she immediately moved her joystick back and forth to correspond to them. Our robot arm moved similarly to Belle's real arm. So did Srinivasan's. Belle and the robots moved in synchrony (同步), like dancers choreographed (设计舞蹈动作) by the electrical impulses sparking in Belle's mind. In the two years since that day, our labs and several others have advanced neuroscience, computer science and microelectronics to create ways for rats, monkeys and eventually humans to control mechanical and electronic machines purely by "thinking through," or imagining the motions. Our immediate goal is to help a person who has been unable to move by a neurological (神经的) disorder or spinal cord (脊髓) injury, but whose motor cortex is spared, to operate a wheelchair or a robotic limb.

单选题Jack {{U}}consumes{{/U}} a pound of cheese a day. A. eats B. drinks C. buys D. produces

单选题He endured great pain before he finally expired. A. fired B. resigned C. died D. retreated

单选题Losing Weight Girls as young as 10 years old are dieting and in danger of developing unhealthy attitudes about weight, body image and food, a group of Toronto researchers reported Tuesday. Their study of 2,279 girls aged 10 to 14 showed that while the vast majority had healthy weights, nearly a third felt they were overweight and were trying to lose pounds. Even at the tender age of 10, nearly 32 per cent of girls felt "too fat" and 31 per cent said they were trying to diet. McVey, a researcher at the Hospital for Sick Children in Toronto, and her colleagues analyzed data collected in a number of surveys of southern Ontario school girls between 1993 and 2003, reporting their findings in Tuesday"s issue of the Canadian Medical Association Journal. Nearly 80 percent of the girls had a healthy body weight and only 7.2 per cent were considered overweight using standard weight-to-height ratios. Most researchers suggest the rate of overweight children in this country is several times higher than that figure. Nearly 30 percent of the girls reported they were currently trying to lose weight, though few admitted to dangerous behavior such as self-induced vomiting. Still, a test that measured attitudes towards eating showed 10.5 per cent of survey participants were already at risk of developing an eating disorder. "We"re not talking about kids who"ve been prescribed a diet because they"re above average weight or overweight. We"re talking about children who are within a healthy weight range. And they have taken it upon themselves to diet to lose weight," McVey said, acknowledging she found the rates disturbing. She said striking a balance between healthy weights and healthy attitudes towards food and body image is a complex task, with no easy solutions.

单选题I asked Lily whether she wanted to go swimming with me and she nodded .

单选题The Effects of Global Warming on Weather There are hidden factors which scientists call "feedback mechanisms". No one knows quite how they will interact with the changing climate. Here"s one example: plants and animals adapt to climate change over centuries. At the current estimate of half a degree centigrade of warming per decade, vegetation (植物) may not keep up. Climatologist James Hansen predicts climate zones will shift toward the poles by 50 to 75 kilometers a year—faster than trees can naturally migrate. Species that find themselves in an unfamiliar environment will die. The 100-kilometer-wide strip of forest running through Canada, the USSR and Scandinavia could be cut by half. Millions of dying trees would soon lead to massive forest fires, releasing tons of CO 2 and further boosting global warming. There are dozens of other possible "feedback mechanism". Higher temperatures will fuel condensation and increase cloudiness, which may actually damp down global warming. Others, like the "albedo" effect, will do the opposite. The "albedo" effect is the amount of solar energy reflected by the earth"s surface. As northern ice and snow melts and the darker sea and land pokes (戳) through, more heat will be absorbed, adding to the global temperature increase. Even if we were to magically stop all greenhouse-gas emissions tomorrow the impact on global climate would continue for decades. Delay will simply make the problem worse. The fact is that some of us are doing quite well the way things are. In developed world prosperity has been built on 150 years of cheap fossil fuels. Material progress has been linked to energy consumption. Today 75 percent of all the world"s energy is consumed by a quarter of the world"s population. The average rich-world resident adds about 3.2 tons of CO 2 yearly to the atmosphere, more than four times the level added by each Third World citizen. The US, with just seven percent of the global population, is responsible for 22 percent of global warming.

单选题Personal Search Agent Hunting for a job late last year, Lawyer Gant Redmon stumbled across Career Builder, a job database on the Internet. He searched it with no success but was attracted by the site"s "personal search agent". It"s an interactive feature that lets visitors key in job criteria such as location, title, and salary, then E-mails them when a matching position is posted in the database. Redmon chose the keywords legal, intellectual property and Washington, D.C. Three weeks later, he got his first notification of an opening. "I struck gold," says Redmon, who E-mailed his resume to the employer and won a position as in-house counsel for a company. With thousands of career-related sites on the Internet, finding promising openings can be time-consuming and inefficient. Search agents reduce the need for repeated visits to the databases. But although a search agent worked for Redmon, career experts see drawbacks. Narrowing your criteria, for example, may work against you: "Every time you answer a question you eliminate a possibility," says one expert. For any job search, you should start with a narrow concept—what you think you want to do—then broaden it. "None of these programs do that," says another expert. "There"s no career counseling implicit in all of this." Instead, the best strategy is to use the agent as a kind of tip service to keep abreast of jobs in a particular database ; when you get E-mail, consider it a reminder to check the database again. "I would not rely on agents for finding everything that is added to a database that might interest me," says the author of a job-searching guide. Some sites design their agents to tempt job hunters to return. When Career Site"s agent sends out messages to those who have signed up for its service, for example, it includes only three potential jobs—those it considers the best matches. There may be more matches in the database; job hunters will have to visit the site again to find them—and they do. "On the day after we send our messages, we see a sharp increase in our traffic," says Seth Peets, vice president of marketing for Career Site. Even those who aren"t hunting for jobs may find search agents worthwhile. Some use them to keep a close watch on the demand for their line of work or gather information on compensation to arm themselves when negotiating for a raise. Although happily employed, Redmon maintains his agent at Career Builder. "You always keep your eyes open," he says. Working with a personal search agent means having another set of eyes looking out for you.

单选题Hack The first big-name hackers included Steve Wozniak, Bill Gates and Linus Torvalds, all now highly recognizable names behind many of the computer technologies used today. These early hackers had a love of technology and a compelling need to know how it all worked, and their goal was to push programs beyond what they were designed to do. Back then, the word hacker didn"t have the negative connotation it has today. The original hacker ethic, rooted out of simple curiosity and a need to be challenged, appears to be dead. The objectives of early hackers are a far cry from the goals of today"s hackers. The motivation of the new breed of hackers appears not to be curiosity, or a hunger for knowledge, as it used to be. Instead, most of today"s hackers are driven by greed, power, revenge, or some other malicious intent, treating hacking as a game or sport, employing the tools that are readily available via the Internet. The rate of security attacks is actually outpacing the growth of the internet. This means that something besides the growth of the Internet is driving the rise in security attacks. Here are some realities you should know about: Operating systems and applications will never be secure. New vulnerabilities will be introduced into your environment every day. And even if you ever do get one operating system secure, there will be new operating systems with new vulnerabilities—phones, wireless devices, and network appliances. Employees will never keep up with security policies and awareness. It doesn"t matter how much you train and educate your employees. If your employees disregard warnings about the hazards of opening questionable e-mail attachments, how are you going to educate them about properly configuring firewalls and intrusion detection systems for their PCs? Managers have more responsibility than ever. And on top of the realities listed above, security managers are being asked to support increasing degrees of network availability and access. There are some good security measures you can take: Employ a layer 7, full-inspection firewall. Automatically update your anti-virus at the gateway, server and client. Keep all of your systems and applications updated. Hackers commonly break into a website through known security holes, so make sure your servers and applications are patched and up to date. Turn off unnecessary network services. Eliminate all unneeded programs. Scan network for common backdoor services—use intrusion detection systems, vulnerability scans, anti-rims protection.

单选题Good teamwork has played an important role in the company's success.A. placeB. gameC. effectD. part

单选题According to the passage, natural sounds include all of the following EXCEPT