单选题The students take a ______ test in March, and the main exam is in July. A. previous B. preliminary C. preceded D. elementary

单选题Woman: Grey says he's going to take three extra classes.Man: He's got to be kidding.Question: What does the man mean?

单选题 Inform the manager if you are on medication that makes you drowsy.

单选题Benjamin West was an (eighteenth-century) American artist (who) influenced British painters (just so much) as he did (other) American artists.

单选题It was clear that the storm ______ his arrival by two hours. A. retarded B. retired C. refrained D. retreated

单选题 SECTION A MULTIPLE-CHOICE QUESTIONS In this section there are several passages followed by ten multiple-choice questions. For each question, there are four suggested answers marked A, B, C and D. Choose the one that you think is the best answer and mark your answers on ANSWER SHEET TWO. PASSAGE ONE In 1943 Germany's submarines—the U-boats—were winning the battle of the Atlantic. Suddenly Germany's U-boat losses doubled in one month. In three months nearly 100 U-boats were sunken, mostly by aircraft. What happened? As soon as it became possible to fit radar in the British coastal command aircraft, there was a change. Radar allowed the planes to search large areas of the sea, to find a submarine even at night and in fog, and to attack before the U-boat could go under the water. The Germans began to lose U-boat to these attacks. They guessed that the aircraft were using radar, and they succeeded in finding out the details of radar. German scientists quickly developed an instrument which picked up the radar signal and gave the U-boat warning. The new instruments allowed the Germans to come to the surface at night and destroy Allied ships. That is when they began to win the Battle of the Atlantic. Then the British developed a new type of radar set which used a much shorter wavelength. In a few months it was so dangerous for a U-boat to come up that the battle of the Atlantic was almost at an end. That is only one example of the many uses of radar in war. What about its uses in peace? Radar has made a great difference to the life of a ship's officer. The radar screen in the wheelhouse shows him every ship that is near him, every piece of land, every buoy. And he can see them clearly at night or in thick fog. He can measure their distance from his own ship, and he knows the speed of the other ships and the direction they are traveling in. Radar is a great help to the pilot of an airliner too. Even in thick fog the officers in the control tower at the airport can see his aircraft. They know its exact position—height, distance, direction, speed. They can talk down the pilot to the point where he can actually see the runway. With even more recent systems, using a combination of radar and other instruments on the aircraft and on the ground, the pilot can now land completely blind in perfect safety. The airport usually has radar of more than one kind. A very narrow, pencil-like beam is used to discover the exact position of a particular aircraft. The aerial which sends out the signal and receives the reflected signal is pointed straight at the aircraft. A narrow beam of that kind is not suitable for search over a wide area in order to find all aircraft that are near the airport. So a separate rotating aerial is used for that purpose. The original radar combined these two things, as its English name showed: Radio Detection and Ranging. PASSAGE TWO Many of the grand challenges of today and the future are found in the question: 'How are we going to solve the problems and make serious improvements in industrial manufacturing, disease control, environmental pollution control, global climate change, food production, transportation, communications, and others?' Nanotechnology (纳米技术) promises to make revolutionary contributions. Within the next few years we can expect to see major improvements. Here are some possibilities of the things to come. Nanotechnology is fundamentally changing the way materials and devices will be produced in the future. Nanostructures, ceramics, polymers, metals, and other materials will have greatly improved mechanical properties. In fact, with the ability to build things atom-by- atom and molecule-by-molecule there will be new classes of structural materials. Nanotechnology will enable products to be lighter, stronger, smarter, cheaper, cleaner, and more precise. The ability to synthesize nanoscale building blocks with precisely controlled size and composition and then to assemble them into larger structures with unique properties and functions will revolutionize segments of the materials manufacturing industry. Nanotechnology is expected to bring about lighter, stronger, and programmable materials; reductions in life- cycle costs through lower failure rates; innovative devices based on new principles architectures; and use of molecular or cluster manufacturing. Nanotechnology will provide new tools for medicine. It could radically change the way surgery is done. It will make it possible to do molecular-scale surgery to repair and rearrange cells. Since disease is the result of physical disorder, misarranged molecules and cells, medicine at this level should be able to cure most diseases. Mutations in DNA could be repaired and cancer cells, toxic chemicals, and viruses could be destroyed through use of medical nanodevices. Nanotechnology-enabled increases in computational power will permit the characterization of macromolecular networks in realistic environments. Such simulations will be essential elements in the development of biocompatible implants and in the drug discovery process. Nanotechnology has the potential to significantly impact energy efficiency, storage, and production. Nanotechnology can change the economics of energy production. PASSAGE THREE The livelihood of each species in the vast and intricate assemblage of living things depends on the existence of other organisms. This interdependence is sometimes subtle, sometimes obvious. Perhaps the most straightforward dependence of one species on another occurs with parasites, organisms that live on or in other living things and derive nutrients directly from them. The parasitic way of life is widespread. A multitude of microorganisms (including viruses and bacteria) and an army of invertebrates—or creatures lacking a spinal column (including insects and many different types of worms)—make their livings directly at the expense of other creatures. In the face of this onslaught, living things have evolved a variety of defense mechanisms for protecting their bodies from invasion by other organisms. Certain fungi and even some kinds of bacteria secrete substances known as antibiotics into their external environment. These substances are capable of killing or inhibiting the growth of various kinds of bacteria that also occupy the area, thereby eliminating or reducing the competition for nutrients. The same principle is used in defense against invaders in other groups of organisms. For example, when attacked by disease-causing fungi or bacteria, many kinds of plants produce chemicals that help to ward off the invaders. Members of the animal kingdom have developed a variety of defense mechanisms for dealing with parasites. Although these mechanisms vary considerably, all major groups of animals are capable of detecting and reacting to the presence of 'foreign' cells. In fact, through the animal kingdom, from sponges to certain types of worms, shellfish, and all vertebrates (creatures possessing a spinal column), there is evidence that transplants of cells or fragments of tissues into an animal are accepted only if they come from genetically compatible or closely related individuals. The ability to distinguish between 'self' and 'nonself', while present in all animals, is most efficient among vertebrates, which have developed an immune system as their defense mechanism. The immune system recognizes and takes action against foreign invaders and transplanted tissues that are treated as foreign cells. PASSAGE FOUR Interest is steadily spreading from a minority of enthusiasts in developing renewable sources of energy—wind, wave and solar power, tidal and geothermal energy. Additional support for them has come with a proposal to explore the untapped sources of hydroelectric power in Scotland. The details are presented by Mr. William Manser in a study called 'The Case for an Inquiry into Hydroelectric Generation in the North of Scotland'. He calls for an expert committee to look at the developments possible for hydroelectric sites and, more important, for means of financing them. There is a clear industrial connection in Mr. Manser's study because it was done for the Federation of Civil Engineering Contractors; hydroelectric schemes, by definition, have a large civil engineering component in them. Mr. Manser estimates that wind power could theoretically provide more than 7 percent of electricity supply in the United Kingdom if suitable sites for generators could be found. However, the practical viability of wind power generation is not likely to be understood anytime soon. The best developed and most suitable form of renewable energy is in his view, hydropower. The technology has been developed over centuries and is still progressing. At present it is the cheapest form of electricity generation. Mr. Manser examined past surveys of the north of Scotland and identified several as suitable for hydroelectric generation. Those are in the remote areas, usually of great natural beauty. But Mr. Manser says a well-designed dam can be impressive in itself. It is also possible to make installation as unobtrusive as possible, to the point of burying parts of them. Hydro- generation involves no water pollution, or smoke creation. The main trouble, as appears from his report, is financing an undertaking which has a heavy initial capital cost, and very low running costs. However, Mr. Manser does not see that as an unfamiliar position for the electricity industry. He cites the proposed construction of the new nuclear power station at Sizewell in Suffolk, which will have a high initial capital cost. The argument at Sizewell that the reason for the expenditure is that the capital will provide a benefit in lower costs and higher returns in the long term, applies equally to hydro- electric generation.

单选题The problem has been ______ my mind all day. A. preying on B. getting at C. taking on D. seeing to

单选题—What will happen at the meeting tonight? —We are going to talk about the problem______at the last meeting.

单选题In no way ______ from practice. A. theory can be separated B. theory is separated C. can theory be separated D. has theory been separated

单选题Whenever work is being done, energy ______ from one form into another. A. converts B. converted C. is converted D. is being converted

单选题People and animals that are _________ are hostile and unfriendly. A. inimical B. derelict C. facetious D. aberrant

单选题 The amount of floating plastic trapped in a north Atlantic current system hasn't got any bigger in 22 years, despite more and more plastic being thrown away. Since 1986 students taking samples of plankton (浮游生物) in the Atlantic and Caribbean Oceans have also noted when their nets caught plastic litter. Kara Lavender and colleagues at the Sea Education Association in Woods Hole, Massachusetts, analysed the data, and found that of 6,136 samples recorded, more than 60 per cent included pieces of plastic, typically just millimetres across. The areas of highest plastic concentration are within the north Atlantic sub-tropical gyre (环流), where currents gather the litter. Lavender and her team were surprised to find that the amount of floating plastic had not increased in the gyre. Although it has been illegal since the 1970s for ships to throw plastic overboard, Lavender thinks that the overall rate of plastic rubbish reaching the ocean will have increased, given the fivefold increase in global production of plastic since 1976. 'Where the extra plastic is going is the big mystery,' she says. Plastic resists bio-degradation and can last decades or more in the ocean. Eventually sunlight and wave motion break it into smaller pieces, which can be harmful to marine life—blocking the stomachs of fish and seabirds, for example. Some experts suggest that the plastic might be degrading into pieces small enough to pass through the 0.3-millimetre-mesh nets used in the study, or becoming coated in biofilms and sinking out of range of the nets. However it is unclear why the rate of degradation during the study period should have increased to offset the extra plastic going into the ocean. Lavender says it is unlikely that ocean currents are pushing plastic out of the gyre, although Simon Boxall of the National Oceanography Centre in Southampton, UK, who wasn't involved in the study, disagrees. He says the Atlantic gyre has an exit strategy in the form of the Gulf Stream. 'We've seen high levels of plastic in the Arctic.' he says. Wherever it is going at the moment, the plastic on our oceans will eventually be broken down into microscopic pieces and individual molecules whose environmental effect is unknown. 'The million-dollar question is, is it causing any damage?' says Boxall. 'When plastic particles get so small are they just like fibre going through the system? Some studies suggest that persistent chemicals in newer plastics function as endocrine (内分泌) disruptors and simulated hormones.' And this fine-grained plastic is very long-lived. 'The depressing thing is it's likely to remain in the oceans essentially forever,' says Lavender.

单选题______ student with a little common sense should be able to answer the question.

单选题After the surface is polished, a design is ______ or painted.

单选题We'll all take a vacation in the mountains as soon as I finish working ______ my project.

单选题How much of the world's land surface is at risk of becoming desert?

单选题Since she was alone, she opened the door ______, leaving the chain lock fastened. A.warily B.consciously C.audaciously D.recklessly