单选题The Science of the Future Until recently, the "science of the future" was supposed to be electronics and artificial intelligence. Today it seems more and more likely that the next great breakthroughs in technology will be brought through a combination of those two sciences with organic chemistry and genetic engineering. This combination is the science of biotechnology. Organic chemistry enables us to produce marvelous synthetic (合成的) materials. However, it is still difficult to manufacture anything that has the capacity of wool to conserve heat and also to absorb moisture. Nothing that we have been able to produce so far comes anywhere near the combination of strength, lightness and flexibility that we find in the bodies of ordinary insects. Nevertheless, scientists in the laboratory have already succeeded in "growing" a material that has many of the characteristics of human skin. The next step may well be "biotech hearts and eyes" which can replace diseased organs in human beings. These will not be rejected by the body, as is the case with organs from humans. The application of biotechnology to energy production seems even more promising. In 1996 the famous science-fiction writer, Arthur C. Clarke, many of whose previous predictions have come true. He said that we may soon be able to develop remarkably cheap and renewable sources of energy. Some of these power sources will be biological. Clarke and others have warned us repeatedly that sooner or later we will have to give up our dependence on non-renewable power sources. Coal, oil and gas are indeed convenient. However, using them also means creating dangerously high levels of pollution. It will be impossible to meet the growing demand for energy without increasing that pollution to catastrophic (灾难性的) levels unless we develop power sources that are both cheaper and cleaner. It is attempting to think that biotechnology or some other "science of the future" can solve our problems. Before we surrender to that temptation we should remember nuclear power. Only a few generations ago it seemed to promise limitless, cheap and safe energy. Today those promises lie buried in a concrete grave in a place called Chernobyl, in the Ukraine. Biotechnology is unlikely, however, to break its promises in quite the same or such a dangerous way.

单选题They have the capability to destroy the enemy in a few days.

单选题The Greatest Mystery of Whales The whale is a mammal-warm-blooded, air-breathing, giving birth to its young alive. sucking them-and, like all mammals, originated on land. There are many signs of this. Its front flippers (鳍足), used for steering and stability, are traces of feet. Immense strength is built into the great body of the big whales, and in fact most of a whale's body is one gigantic muscle. The blue whale's pulling strength has been estimated at 400 horsepower. One specimen was reported to have towed (牵引) a whaling vessel for seven hours at the rate of eight knots. An enraged whale will attack a ship. A famous example of this was the fate of whaler Essex, which was sunk off the coast South America early in the last century. More recently, steel ships have had their plates buckled in the same way. Sperm whales were known to seize the old-time whaleboats in their jaws and crush them. The greatest mystery of whales is their diving ability. The sperm whale can dive on the bottom for his favorite food, the octopus. In that search he is known to go as far down as 3,200 feet, where the pressure is 1,400 pounds, to the square inch. Doing so he will remain submerged as long as one hour. Two feats(壮举) are involved in this: storing up enough oxygen (all whales are air-breathed) and withstanding the great change in pressure. Just how he does it scientists have not determined. It is believed that some of the oxygen is stored in a special system of blood vessels, rather than just held in the lungs. And it is believed that a special kind of oil in his head is some sort of compensating mechanism that automatically adjusts the internal pressure of his body. But since you can't bring a live whale into the laboratory for study, no one knows just how these things work.

单选题He denies involvement with either drugs or the CIA.

单选题We can take control aggressively of the way we age and delay body Udeterioration/U that causes activities to be severely limited.

单选题A young man is being hailed a hero tonight after rescuing two children.A. reportedB. praisedC. provedD. caught

单选题1. Digital Realm In the digital realm the next big advance will be voice recognition. The rudiments are already here but in primitive form. Ask a computer to "recognize speech," and it is likely to think you want it to "wreck a nice beach." But in a decade or so we'll be able to chat away and machines will soak it all in. Microchips will be truly embedded in our lives when we can talk to them. Not only to ourcomputers; we'll also able to chat our automobile navigation systems, telephone consoles, browsers, thermostats, VCRs, microwaves and any other devices we want to boss around. That will open the way to the next phase of the digital age: artificial intelligence. By our providing so many thoughts and preferences to our machines each day, they'll accumulate enough information about how we think so that they'll be able to mimic our minds and act as our agents. Scary, huh? But potentially quite useful. At least until they don't need us anymore and start building even smarter machines they can boss around. The law powering the digital age up until now has been Gordon Moore's: that microchips will double in power and halve in price every 18 months or so. Bill Gates rules because early on he acted on the assumption that computing power—the capacity of microprocessors and memory chips—would become nearly flee; his company kept churning out more and more lines of complex software to make use of the cheap bounty. The law that will power the next few decades is that the bandwidth (the capacity of fiber-optic and other pipelines to carry digital communications) will become nearly free. Along with the recent advances in digital switching and storage technologies, this means a future in which all forms of content—movies, music, shows, books, data, magazines, newspapers, your aunt's recipes and home videos—will be instantly available anywhere on demand. Anyone will be able to be a producer of any content; you'll be able to create a movie or magazine, make it available to the world and charge for it, just like Time Warner! The result will be a transition from a mass. market world to a personalized one. Instead of centralized factories and studios that distribute or broadcast the same product to millions, technology is already allowing products to be tailored to each user You call subscribe to news sources that serve up only topics and opinions that fit your fancy. Everything from shoes to steel can be customized to meet individual wishes.

单选题The great changes of the city (astonished) every visitor to that city．

单选题Finding a job can be depressing and disappointing, and therefore it is important that you are prepared.A. exploitingB. frustratingC. profitingD. misleading

单选题In order to limit the damage and to prevent some of the suffering resulting from earthquakes, scientists are working on ways to enable accurate prediction, Special instruments are used to help people record, for example, shaking of the earth. Scientist are trying to find methods that will enable them to indicate the exact time, location and size of an earthquake. Certain phenomena have been observed which are believed to be the signs of imminent(即将发生的) earthquakes. These include strange behaviours of some animals, the changes in the content of mineral water, etc. The magnetic properties of rocks may also display special pattern before major earthquakes happen. Signs of imminent earthquakes include all the following BUTA. strange behaviours of animals.B. changes in the content of mineral water.C. the magnetic properties of rocks.D. dramatic change in climat

单选题Housewives who do not go out to work often feel they are not working to their full ability .

单选题What is said about cell phone use in the mid-1980s in paragraph 5?

单选题These figures do not take into account the changes that have taken place in recent years. A. consider B. call C. catch D. cancel

单选题We tried to restrict our conversation to arguments relevant to the topic.

单选题Calculating Crime When you think about math, you probably don't think about breaking the law, solving mysteries or finding criminals. But a mathematician in Maryland does, and he has come up with mathematical tools to help police find criminals. People who solve crimes look for patterns that might reveal the identity of the criminal. It's long been believed, for example, that criminals will break the law closer to where they live. simply because it's easier to get around in one's own neighborhood. If police see a pattern of robberies in a certain area, they may look for a suspect who lives near the crime scenes. So, the farther away from the area a crime takes place, the less likely it is that the same criminal did it. But Mike O'Leary, a mathematician at Towson University in Maryland, says that this kind of approach may be too simple. He says that police may get better clues to the location of an offender's home base by combining these patterns with a city's layout and historical crime records. The records of past crimes contain geographical information and can reveal easy targets--that is, the kind of stores that might be less difficult to rob. Because these stores are along roads, the locations of past crimes contain information about where major streets and intersections(十字路口) are. O'Leary is writing a new computer program that will quickly provide this kind of information for a given city. His program also includes information about the people who live in the city, and information about how a criminal's patterns change with age. (It's been shown, for example, that the younger the criminal, the closer to home the crime. ) Other computer programmers have worked on similar software, but O'Leary's uses more math. The mathematician plans to make his computer program available, free of charge, to police departments around the country. The program is just one way to use math to fight crime. O'Leary says that criminology--the study of crime and criminals contains a lot of good math problems. "I feel like I'm in a gold mine and I'm the only one. who knows what gold looks like." he says. "It's a lot of fun. /

单选题 阅读下面这篇短文，短文后列出7个句子，请根据短文的内容对每个句子做出判断。 {{B}}Changes in Museums{{/B}} Museums have changed. They are no longer places that one "should" visit, they are places to enjoy and learn. At a science museum in Ontario, Canada, you can feel your hair stand on end as harmless electricity passes through your body. At the Metropolitan (成都市的) Museum of Art in New York City, you can look at the seventeenth century instruments while listening to their music. At New York's American Museum of Natural History recently, you can help make a bone-by-bone reproduction of the museum's dinosaur(恐龙), a beast that lived 200 million years age. More and more museum directors are realizing that people learn best when they can somehow become part of what they are seeing. In many science museums, for example, there are no guided tours. The visitor is encouraged to touch, listen, operate, and experiment so as to discover scientific principles for himself. The purpose is not only to provide fun but also to help people feel at home in the world of science. The theory is that people who do not understand science will probably fear it, and those who fear science will not use it to best advantage. One cause of all these changes is the increase in wealth and leisure time. Another cause is the rising percentage of young people in the population. Many of these young people are college students or college graduates, Leon F. Twiggs, a young black professor of art once said, "They see things in a new and different way. They are not satisfied to stand and look at works of art; they want art they can participate(参加) in. "The same is true of science and history.

单选题Avalanche and Its Safety An avalanche is a sudden and rapid flow of snow, often mixed with air and water, down a mountainside. Avalanches are (51) the biggest dangers in the mountains for both life and property. All avalanches are caused by an over-burden of material, typically snowpack, that is too massive and unstable for the slope (52) supports it. Determining the critical load, the amount of over-burden which is (53) to cause an avalanche, (54) a complex task involving the evaluation of a number of factors. Terrain slopes flatter than 25 degrees or steeper than 60 degrees typically have a low (55) of avalanche. Snow does not (56) significantly on steep slopes; also, snow does no (57) easily on fiat slopes. Human-triggered avalanches have the greatest incidence when the snow's angle of rest is (58) 35 and 45 degrees; the critical angle, the angle at which the human incidence of avalanches is greatest, is 38 degrees. The rule of thumb is: A slope that is (59) enough to hold snow but steep enough to ski has the potential to generate an avalanche, regardless of the angle. Additionally, avalanche risk increases with (60) ; that is, the more a slope is disturbed by skiers, the more likely it is that an avalanche will occur. Due to the complexity of the subject, winter travelling in the backcountry is never 100% safe. Good avalanche safety is a continuous (61) , including route selection and examination to the snowpack, weather (62) , and human factors. Several well-known good habits can also (63) the risk. If local authorities issue avalanche risk reports, they should be considered and all warnings should be paid (64) to. Never follow in the tracks of others without your own evaluations; snow conditions are almost certain to have changed since they were made. Observe the terrain and note obvious avalanche paths where plants are (65) or damaged. Avoid traveling below others who might trigger an avalanche.

单选题She is incapable of doing the demanding job.

单选题US citizens and businesses have long complained that many of the government's rules are written in overly technical, complicated language. The Occupational Safety and Health Administration (OSHA) has particularly been the subject of much criticism and debate. This agency makes and enforces rules to ensure employee health and safety on the job. The problem is, even after reading the roles several times, employees often don't know what is expected of them. OSHA has been the subject of much criticism mainly becauseA. its rules are wrongly expressed.B. its rules focus on too many details.C. its rules use many technical words.D. its rules are beyond comprehension.