单选题We have to take some ______ to put it right.A. decisionsB. advantagesC. sidesD. measures

单选题I didn't help him. I would have Uhowever/U didn't have the money.

单选题The ice is not thick enough to bear the weight of a tank.

单选题TapeStore: A New Tape Storage System TapeStore is a new kind of tape storage system which can store up to 6,000 computer tapes. No other tape storage system can hold as many computer tapes as TapeStore. The tapes look exactly like video cassettes. Many hundreds of data files can be stored on each tape, up to a maximum of 500 million bytes (字节) of data. If you stored the same amount of information on paper, you would need nearly 4.5 billion printed pages. The machine is a tall black box with a mechanical arm. The machine is 2.5 meters high and 3.0 meters wide. This is how it works. Each tape has a code printed on it. You feed the code number into TapeStore, which then looks for the code. As soon as TapeStore locates the code, the arm reaches in and pulls out the tape. The system is very fast. It takes the mechanical arm about 10 seconds to find the tape it is looking for. The machine then searches the tape to extract (提取) the required file, and this takes less than a minute. A human technician would have to locate and remove the tape by hand, and could take at least an hour to find the right file on the tape. Some of the world"s biggest companies, including banks, insurance companies, airlines, telephone companies, utilities and computer centers, have bought the system. They like it particularly because the system guarantees the security of their data. TapeStore was originally developed in Canada and is now being marketed worldwide. In Europe alone, 750 Tape Stores have already been installed at a cost of 480,000 dollars each.

单选题who are mostlikely to benefit from the study?

单选题Superconductor Ceramic (陶瓷) An underground revolution begins this winter. With the flip (轻击) of a switch, 30,000 homes in one part of Detroit will soon become the first in the country to receive electricity transmitted by ice-cold high-performance cables. Other American cities are expected to follow Detroit"s example in the years ahead, which could conserve enormous amounts of power. The new electrical cables at the Frisbie power station in Detroit are revolutionary because they are made of superconductors. A superconductor is a material that transmits electricity with little or no resistance. Resistance is the degree to which a substance resists electric current. All common electrical conductors have a certain amount of electrical resistance. They convert at least some of the electrical energy passing through them into waste heat. Superconductors don"t. No one understands how superconductivity works. It just does. Making superconductors isn"t easy. A superconductor material has to be cooled to an extremely low temperature to lose its resistance. The first superconductors, made more than 50 years ago, had to be cooled to-263degrees Celsius before they lost their resistance. Newer superconducting materials lose their resistance at-143 degrees Celsius. The superconductors cable installed at the Frisbie station is made of a ceramic material that contains copper, oxygen, bismuth (铋) , strontium (锶) , and calcium (钙). A ceramic is a hard, strong compound made from clay or minerals. The superconducting ceramic has been fashioned into a tape that is wrapped lengthwise around a long tube filled with liquid nitrogen. Liquid nitrogen is super cold and lowers the temperature of the ceramic tape to the point where it conveys electricity with zero resistance. The United States loses an enormous amount of electricity each year to resistance. Because cooled superconductors have no resistance, they waste much less power, other cities are watching the Frisbie experiment in the hope that they might switch to superconducting cable and conserve power, too.

单选题The researchers have just {{U}}completed{{/U}} a study of driving situations. A. started B. finished C. changed D. made

单选题The project required ten years of diligent research.

单选题World Crude Oil Production May Peak a Decade Earlier Than Some Predict? In a finding that may speed efforts to conserve oil, scientists in Kuwait predict that world conventional crude oil production will peak in 2014. This prediction is almost a decade earlier than some other predictions. Their study is in ACS" Energy & Fuels. Ibrahim Nashawi and colleagues point out that rapid growth in global oil consumption has sparked a growing interest in predicting "peak oil". "Peak oil" is the point where oil production reaches a maximum and then declines. Scientists have developed several models to forecast this point, and some put the date at 2020 or later. One of the most famous forecast models is called the Hubbert model. It assumes that global oil production will follow a bell shaped curve. A related concept is that of "Peak Oil". The term "Peak Oil" indicates the moment in which worldwide production will peak, afterwards to start on irreversible decline. The Hubbert model accurately predicted that oil production would peak in the United States in 1970. The model has since gained in popularity and has been used to forecast oil production worldwide. However, recent studies show that the model is insufficient to account for more complex oil production cycles of some countries. Those cycles can be heavily influenced by technology changes, politics, and other factors, the scientists say. The new study describes development of a new version of the Hubbert model that provides a more realistic and accurate oil production forecast. Using the new model, the scientists evaluated the oil production trends of 47 major oil-producing countries, which supply most of the world"s conventional crude oil. They estimated that worldwide conventional crude oil production will peak in 2014, years earlier than anticipated. The scientists also showed that the world"s oil reserves are being reduced at a rate of 2.1 percent a year. The new model could help inform energy-related decisions and public policy debate, they suggest.

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。如果该句提供的是正确信息，请选择A；如果该句提供的是错误信息，请选择B；如果该句的信息文章中没有提及，请选择C。 Hydroponics, the science of growing plants, in water or inert substances, represents one of the most innovative practices in modern agricultural development. Not only does it allow greater of the plant growth process, it permits the production of crops in hostile infertile environments. The first widely publicized soilless gardening experiments were conducted during the 1930s. W. F. Gericke varied nutrient levels among specimens suspended in a gravel substrate (沙砾基质) to demonstrate remarkable alterations in growth. Among the findings that amazed his fellow horticulturists was the production of tomato plants over 6 meters high. The original hydroponics gardens merely consisted of plants floating in water. It was later discovered that the roots could survive in a number of media, as long as they were supplied with sufficient moisture, nutrients and oxygen. A variety of materials are used in recent versions including gravel, sand, peat, sawdust, plastics and so on. Indeed, one of the most productive methods involves suspending plants in air with a Styrofoam support and spraying them occasionally with nutrient solution to keep them moist. Many different kinds of materials are suitable for physically containing plants, yet all of these systems share one trait: the culture solution. This nutrient bath is prepared in a tank by dissolving salts which provide the necessary chemicals for plant metabolism. Constant care must be taken to assure that the sodium chloride(氯化纳)levels in the tank do not reach excessive levels as the plants draw water and minerals out of the solution. The acidity of the tank must also be maintained around 6.0 to 6.5 depending on the specific type of plants being harvested. Although soilless farming is generally more expensive than utilizing fertile land, there are many advantages that make it an important alternative to traditional practices. Herbicides and pesticides are unnecessary because of the controlled environment. The plants also need less space to grow because their nutrient uptake is significantly more efficient. The most outstanding benefit, though, is the ability to produce crops in areas with poor soil conditions or insufficient rainfall.

单选题 Culture, Language and Equality Culture is the sum total of all the traditions, customs, belief and ways of life of a given group of human beings. In this sense, every group has a culture, however savage, undeveloped, or uncivilized it may seem to us. To the professional anthropologist, there is no intrinsic superiority of one culture over another, just as to the professional linguist there is no intrinsic hierarchy among languages. People once thought of the languages of backward groups as savage, undeveloped form of speech, consisting largely of grunts and groans. While it is possible that language in general began as a series of grunts and groans, it is a fact established by the study of “backward” languages that no spoken tongue answers that description today. Most languages of uncivilized groups are, by our most severe standards, extremely complex, delicate, and ingenious pieces of machinery for the transfer of ideas. They fall behind the Western languages not in their sound patterns or grammatical structures, which usually are fully adequate for all language needs, but only in their vocabularies, which reflect the objects and activities known to their speakers. Even in this department, however, two things are to be noted: 1. All languages seem to possess the machinery for vocabulary expansion, either by putting together words already in existence or by borrowing them from other languages and adapting them to their own system. 2. The objects and activities requiring names and distinctions in “backward” languages, while different from ours, are often surprisingly numerous and complicated. A western language distinguishes merely between two degrees of remoteness (“this” and “that”); some languages of the American Indians distinguish between what is close to the speaker, or the person addressed, or remote from both, or out of sight, or in the past, or in the future. This study of language, in turn, casts a new light upon the claim of the anthropologists that all cultures are to viewed independently, and without ideas of rank or hierarchy.

单选题He expressed concern that the ship might be in distress .

单选题下面的短文后列出了7个句子，请根据短文的内容对每个句子做出判断：如果该句提的是正确信息，请选择A：如果该句提的是错误信息，请选择B：如果该句的信息文中没有提及，请选择C。 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 (涂), 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 (图形) tablets and touch screens, but the mouse is still 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 (常规) 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 the mouse ball in the bottom of the mouse rolls over the mouse pad, it presses against and turns two shafts (轴). The shafts are conneected 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 detects (发现) a changing pattern of light, converts the pattern into an electronic signal, and sends the signal (发信号) to the computer through wires in a cable that goes out 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For young children, getting dressed is a complicated business. A. personal B. strange C. funny D. complex

单选题One thing alone makes it almost impossible for men to live in Antarctica and in parts of the Arctic. This one thing is the low temperature-the killing chill of the far North and the polar South. To survive, men must wear the warmest possible clothing. They must build windproof shelters. They must keep heaters going at all times. Not even for moment can they be unprotected against the below-zero temperature. Men have a way of providing for themselves. Polar explorers wrap themselves in warm coats and furs. The cold makes life difficult. But the explorers can stay alive. What about animals? Can they survive? Do we find plants? Do we find life in the Arctic and the Antarctica? Yes. we do. There is life in the oceans. There is life on land. Antarctica, as we have seen, is a cold place indeed. But this has not always been the case. Expedition scientists have discovered that Antarctica may have been much like our own. Explorers have discovered coal in Antarctica. This leads them to believe that Antarctica at one time was a land of swamps and forests. Heat and moisture must have kept the trees in the forests alive. Who call survive the severe cold in the Antarctica and in parts of the Arctic according to the passage?A. The explorers to these areas.B. All expedition scientists.C. Any person with good equipment.D. Only those who are well-equipment.

单选题The coral island nations of the Pacific have a long history Of civilization.

单选题He is certain that the dictionary is just what I want.

单选题All living organisms, Uregardless/U of their unique identity, have certain biological, chemical, and physical characteristics in common.

单选题The new job will provide you with invaluable experience.

单选题A child's actions should be modified by Uimposing/U a system of rewards.