单选题It was so dark that I could hardly see.

单选题Changes in Children About six years ago I was eating lunch in a restaurant in New York City when a woman and a young boy sat down at the next table. I couldn"t help overhearing parts of their conversation. At one point the woman asked: "So, how have you been?" And the boy—who could not have been more than seven or eight years old—replied: "Frankly, I"ve been feeling a little depressed lately. " This incident stuck in my mind because it confirmed my growing belief that children are changing. As far as I can remember, my friends and I didn"t find out we were "depressed" until we were in high school. The evidence of a change in children has increased steadily in recent years. Children don"t seem childlike anymore. Children speak more like adults, dress more like adults and behave more like adults than they used to. Whether this is good or bad is difficult to say, but it certainly is different. Childhood as it once was no longer exists, why? Human development is based not only on innate (天生的) biological states, but also on patterns of access to social knowledge. Movement from one social role to another usually involves learning the secrets of the new status. Children have always been taught adult secrets, but slowly and in stages: traditionally, we tell sixth graders things we keep hidden from fifth graders. In the last 30 years, however, a secret-revelation (揭示) machine has been installed in 98 percent of American homes. It is called television. Television passes information, and indiscriminately (不加区分地) , to all viewers alike, be they children or adults. Unable to resist the temptation, many children turn their attention from printed texts to the less challenging, more vivid moving pictures. Communication through print, as a matter of fact, allows for a great deal of control over the social information to which children have access. Reading and writing involve a complex code of symbols that must be memorized and practiced. Children must read simple books before they can read complex materials.

单选题Older Volcanic Eruptions Volcanoes were more destructive in ancient history, not because they were bigger, but because the carbon dioxide they released wiped out life with greater ease. Paul Wignall from the University of Leeds was investigating the link between volcanic eruptions and mass extinctions. Not all volcanic eruptions killed off large numbers of animals, but all the mass extinctions over the past 300 million years coincided with huge formations of volcanic rock. To his surprise, the older the massive volcanic eruptions were, the more damage they seemed to do. He calculated the "killing efficiency" for these volcanoes by comparing the proportion of life they killed off with the volume of lava (熔岩) that they produced. He found that size for size, older eruptions were at least 10 times as effective at wiping out life as their more recent rivals. The Permian (二叠纪) extinction, for example, which happened 250 million years ago, is marked by floods of volcanic rock in Siberia that cover an area roughly the size of western Europe. Those volcanoes are thought to have pumped out about 10 gigatonnes of carbon as carbon dioxide. The global warming that followed wiped out 80 percent of all marine genera (种类) at the time, and it took 5 million years for the planet to recover. Yet 60 million years ago, there was another huge amount of volcanic activity and global warming but no mass extinction. Some animals did disappear but things returned to normal within ten thousand of years. "The most recent ones hardly have an effect at all," Wignall says. He ignored the extinction which wiped out the dinosaurs 65 million years ago, because many scientists believe it was primarily caused by the impact of an asteroid (小行星). He thinks that older volcanoes had more killing power because more recent life forms were better adapted to dealing with increased levels of CO 2 . Vincent Courtillot, director of the Paris Geophysical Institute in France, says that Wignall"s idea is provocative. But he says it is incredibly hard to do these sorts of calculations. He points out that the killing power of volcanic eruptions depends on how long they lasted. And it is impossible to tell whether the huge blasts lasted for thousands or millions of years. He also adds that it is difficult to estimate how much lava prehistoric volcanoes produced, and that lava volume may not necessarily correspond to carbon dioxide emissions.

单选题The "fact" in Paragraph 2 refers to

单选题Kobe Bryant After 10 seasons wearing the No. 8 on his back, Kobe Bryant will become No. 24 next season. The reason for the surprising decision by the Los Angeles Lakers super guard last week has become a hot topic for debate. Bryant wore No. 24 when he was in early high school, but he changed to No. 33 in his senior year. He switched to No. 8 when he was selected by the Lakers in 1996, and has not been changed since. Bryant has refused to explain the decision until the end of the play-offs (季后赛). So guessing Bryant's motive has become a popular game among NBA fans and newspaper columnists(专栏作家). There are all kinds of speculations. Many say that Bryant wants to leave the past behind and have a fresh start. He has often been criticized for playing to benefit himself and not the team as a whole. Others say that he may be trying to compare himself to Michael Jordan. Jordan was famous for his No. 23 jersey(运动衫). Some, such as NBA Sport columnist Michael Venter, argue that it is "all about money". Bryant will make more money by selling new jerseys to his fans. Some speculations are more about fun. For example, there is an opinion that Kobe is actually just a diehard(非常执著的) fan of the popular TV drama"24". All this talk has turned the number change into a major issue. It seems that there is a lot of fuss (大惊小怪) over something that should be pretty simple. Jersey numbers have their own special significance in American sports, especially basketball. Players choose their number when they join a team and they usually stick with that number for the rest of their career. When a great player retires, his team will honor him by retiring his number. To some extent, the jersey is the player, and the player is the jersey. Thus, when you see the famous No. 23 for the Chicago Bulls, you immediately think about Michael Jordan. A No. 32 Miami Heats jersey recalls the image of Shaquille O'Neal, and the Houston Rockets No. 11 belongs only to Yao Ming. Lots of stories are behind players' jersey number selections. Jordan said that he chose No. 23 because it was roughly half of 45．Jordan's elder brother wore the No. 45 in college. Yao Ming once revealed that the No. 11 stands for two people in love—meaning him and his girlfriend Ye Li.

单选题Biologists have ascertained that specialized cells convert chemical energy into mechanical energy.

单选题She has been the subject of massive media coverage.A. extensiveB. negativeC. expensiveD. active

单选题The new technological revolution in American newspapers has brought increased {{U}}issue volume{{/U}}, a wider range of publications and an expansion of newspaper jobs. A. manipulation B. reproduction C. circulation D. penetration

单选题Pronouncing a Language Pronouncing a language is a skill. Every normal person is an expert in the skill of pronouncing his own language; but few people are even fairly proficient at pronouncing foreign languages. Now there are many reasons for this, some obvious, some perhaps not so obvious. But I suggest that the basic reason why people in general do not speak foreign languages very much better than they do native language is that they fail to understand the true nature of the problem of learning to pronounce. Far too many people fail to realize that pronouncing a foreign language is a skill--one that needs careful training of a special kind, and one that cannot be gained by just leaving it to take care of itself. I think even teachers of language, while realizing the importance of a good accent, often neglect, in their practical teaching, the branch of study concerned with speaking the language. So the first point I want to make is that English pronunciation must be taught; the teacher should be prepared to devote some of the lesson time to this, and get the student to feel that here is a matter worthy of receiving his close attention. So, there should be occasions when other aspects of English, such as grammar or spelling, are allowed for the moment to take second place. Besides this question of the time given to pronunciation, there are two other requirements for the teacher: the first, knowledge; the second, technique. It is also possible to get a clear mental picture of the relationship between the sounds of different languages, between the speech habits of English people and those, say, of your students. Unless the teacher has such a picture, any comments he may make on his students' pronunciation are unlikely to be of much use, and lesson time spent on pronunciation may well be time wasted.

单选题Computer Mouse The basic computer mouse is an amazingly clever invention with a relatively simple design that allows US to point at things on the computer and it is very productive. Think of all the things you can do with a mouse like selecting text for copying and pasting, drawing, and even scrolling on the page with the newer mice with the wheel. Most of us use the computer mouse daily without stopping to think how it works until it gets dirty and we have to learn how to clean it. we learn to point at things before we learn to speak, So the mouse is a very natural pointing device. Other computer pointing devices include light pens, graphics tablets and touch screens, but the mouse isstill our workhorse. The computer mouse was invented in 1964 by Douglas Englehart of Stanford University. As computer screens became more popular and arrow keys were used to move around a body of text, it became clear that a pointing device that allowed easier motion through the text and even selection of text would be very useful. The introduction of the mouse, with the Apple Lisa computer in 1983, really started the computer public on the road to relying on the mouse for routine computer tasks. How does the mouse work? we have to start at the bottom, so think upside down for now. It all starts with the mouse ball. As me mouse ball in the bottom of the mouse rolls over the mouse pad, it presses against and turns two shafts. The shafts are connected to wheels with several small holes in them. The wheels have a pair of small electronic light-emitting devices called light-emitting diodes(LED) mounted on either side. One LED sends a light beam to the LED on the other side. As the wheels spin and a hole rotates by, the light beam gets through to the LED on the other side. But a moment later the light beam is blocked until the next hole is in place. The LED detect a changing pattern of fight, converts the pattern into an electronic signal, and sends the signal to the computer through wires in a cable that goes out of the mouse body. This cable is the tail that helps give the mouse its name. The computer interprets the signal to tell it where to position the Cursor on the computer screen. So far we have only discussed the basic computer mouse that most of you probably have or have used. One problem with this design is that the mouse gets dirty as the ball rolls over the surface and picks up dirt, Eventually you have to clean your mouse. The newer optical mice avoid this problem by having no moving parts.

单选题The son was so concerned about the illness of his father.A. seriousB. happyC. luckyD. worried

单选题The story was touching .

单选题As a writer, he turned out three novels that year. A. refused B. read C. produced D. accepted

单选题{{B}}第一篇{{/B}} {{B}}Effects of Environmental Pollution{{/B}} If pollution continues to increase at the present rate, formation of aerosols (浮质) in the atmosphere will cause the onset (开始) of an ice age in about fifty year's time. This conclusion reached by Dr S. I. Rasoo1 and Dr S. H. Scheider of the United States Goddard Space Flight Center, answer the apparently conflicting questions of whether an increase in the carbon dioxide (二氧化碳) content of the atmosphere will cause the Earth warm up or increasing the aerosol question is dominant. Two specters haunting conservationists have been the prospect that environmental pollution might lead to the planet's becoming unbearably hot or cold. One of these ghosts has now been laid, because it seems that even an increase in the amount of carbon dioxide in the atmosphere to eight times its present value will produce an increase in temperature of only 2℃, which would take place over several thousand years. But the other problem now looms larger than ever. Aerosols are collection of small liquid or solid particles dispersed in air or some other medium. The particles are all so tiny that each is composed of only a few hundred atoms. Because of this they can float in the air for a very long time. Perhaps the most commonly experienced aerosol is industrial smog (烟雾) of the kind that plagued London in the 1950s and is an even greater problem in Los Angeles today. These collections of aerosols reflect the Sun's heat and thereby cause the Earth to cool. Dr Rasoo1 and Dr Schneider have calculated the exact effect of a dust aerosol layer just above the Earth's surface in the temperature of the planet. As the layer builds up, the present delicate balance between the amount of heat absorbed from the Sun and the amount radiated from the Earth is disturbed. The aerosol layer not only reflects much of the Sun's light but also transmits the infrared (红外线) radiation from below. So, while the heat input to surface drops, the loss of heat remains high until the planet cools to a new balanced state. Within fifty years, if no steps are taken to stop the spread of aerosols in the atmosphere, a cooling of the Earth by as much as 3.5~C seems inevitable. If that lasts for only a few years it would start another ice age, and because the growing ice caps at each pole would themselves reflect much of the Sun's radiation it would probably continue to develop even if the aerosol layer were destroyed. The only bright spot in this gloomy forecast lies in the hope expressed by Dr Rasoo1 and Dr Schneider that nuclear powder may replace fossil fuels in time to prevent the aerosol content of atmosphere from becoming critical.

单选题From my Ustandpoint/U, you know, this thing is just ridiculous.

单选题Agriculture made possible a more stable and a secure life. With the flourishing of agriculture, Neolithic(新石器时代的)peoples were able to free themselves out of savage life. They needn't live in caves, searching for food from dawn until dusk, chasing beasts or being chased by them. They needn't worry where to find their next meal. Agriculture made it possible for them to devote their abundant free time and energy to erecting towns and eventually cities, creating art and literature and beginning a new civilization. Indeed, they were responsible for many fundamental inventions that the modem world takes for granted. Flourishing agriculture made possible a stable and secure life becauseA. people were able to free themselves out of savage life.B. they had to worry about foods all the time.C. they had time to find new homes.D. they had more time and energy for fun.

单选题While they were away on vacation, they allowed their mail to accumulate at the post office.

单选题This is a subject that has now moved into the political domain.A. extentB. zoneC. fieldD. region

单选题I am heartily {{U}}grateful{{/U}} to your help. A. helpful B. hateful C. delightful D. thankful

单选题Nitrogen is the most plentiful gas in the atmosphere.