单选题At last she left her house and hurried to the airport only ______ the plane flying away.

单选题Nowadays advertising costs are no longer in reasonable______ to the total cost of the product.

单选题Deserts and high mountains have always been a______to the movement of people.

单选题During his lifetime he was lucky to accumulate quite a fortune.

单选题Biologists have ascertained that specialized cells convert chemical energy into mechanical energy. A. determined B. argued C. pretended D. hypothesized

单选题A hefty 50% of those from ages 18 to 34 told floe pollsters in the TIME/CNN survey that they ______ "feminist" values. A. share B. regard C. attach D. dominate

单选题The garden looked as if it ______ for years.

单选题The ______ of these good to the others is easy to see.

单选题There is not a Greek word which is the exact ______ of the English word 'stile'.

单选题Why do some desert plants grow tall and thin like organ pipes? Why do most trees in the tropics keep their leaves year round? Why in the Arctic tundra are there no trees at all? After many years without convincing general answers, we now know much about what sets the fashion in plant design. Using terminology more characteristic of a thermal engineer than of a botanist, we can think of plants as mechanisms that must balance their heat budgets. A plant by day is staked out under the Sun with no way of sheltering itself. All day long it absorbs heat. If it did not lose as much heat as it gained, then eventually it would die. Plants get rid of their heat by warming the air around them, by evaporating water, and by radiating heat to the atmosphere and the cold, black reaches of space temperature is tolerable for the processes of life. Plants in the Arctic tundra lie close to the ground in the thin layer of still air that clings there. A foot or two above the ground are the winds of Arctic cold. Tundra plants absorb heat from the Sun and tend to warm up; they probably balance most of their heat budgets by radiating heat to space, but also by warming the still air hat is trapped among them. As long as Arctic plants are close to the ground, they can balance their heat budgets. But if they should stretch up as a tree does, they would lift their working parts, their leaves, into the streaming Arctic winds. Then it is likely that the plants could not absorb enough heat from the Sun to avoid being cooled below a critical temperature. Your heat budget does not balance if you stand tall in the Arctic. Such thinking also helps explain other characteristics of plant design. A desert plant faces the opposite problem from that of an Arctic plant the danger of overheating. It is short of water and so cannot cool itself by evaporation without dehydrating. The familiar sticklike shape of desert plants represents one of the solutions to this problem: the shape exposes the smallest possible surface to incoming solar radiation and provides the largest possible surface from which the plant can radiate heat. In tropical rain forests, by way of contrast, the scorching sun is not a problem for plants because there is sufficient water. This working model allows us to connect the general characteristics of the forms of plants indifferent habitats with factors such as temperature, availability of water, and presence or absence of seasonal differences. Our Earth is covered with a patchwork quilt of meteorological conditions, and the patterns of this patchwork are faithfully reflected by the plants.

单选题A study by scientists in Finland has found that mobile phone radiation can cause changes in human cells that might affect the brain, the leader of the research team said. But Darius Leszczynski, who headed the 2-year study and will present findings next week at a conference in Quebec (魁北克), said more research was needed to determine the seriousness of the changes and their impact on the brain or the body. The study at Finland's Radiation and Nuclear Safety Authority found that exposure to radiation from mobile phones can cause increased activity in hundreds of proteins in human cells grown in a laboratory, he said. "We know that there is some biological response. We can detect it with our very sensitive approaches, but we do not know whether it can have any physiological effects on the human brain or human body," Leszczynski said. Nonetheless, the study, the initial findings of which were published last month in the scientific journal Differentiation, raises new questions about whether mobile phone radiation can weaken the brain's protective shield against harmful substances. The Study focused on changes in cells that line blood vessels and on whether such changes could weaken the functioning of the blood-brain barrier, which prevents potentially harmful substances from entering the brain from the bloodstream, Leszczynski said. The study found that a protein called hsp27 linked to the functioning of the blood-brain barrier showed increased activity due to irradiation and pointed to a possibility that such activity could make the shield more permeable(能透过的), he said. "Increased protein activity might cause cells to shrink—not the blood vessels but the cells themselves—and then tiny gaps could appear between those cells through which some molecules could pass," he said. Leszczynski declined to speculate on what kind of health risks that could pose, but said a French study indicated that headache, fatigue and sleep disorders could result. "These are not life-threatening problems but can cause a lot of discomfort," he said, adding that a Swedish group had also suggested a possible link with Alzheimer's disease. "Where the truth is, I do not know," he said. Leszczynski said that he, his wife and children use mobile phones', and he said that he did not think his study suggested any need for new restrictions on mobile phone use.

单选题The Austrian manufacturing industry consists of a few large organizations, many of which oper ate under government {{U}}auspices{{/U}}.

单选题Officials are supposed to ____ themselves to the welfare and health of the general public.

单选题Many people think of deserts as ______ regions, but numerous species of plants and animals have adapted to life there.

单选题He kept throwing us an apple of discord, we soon quarreled again.

单选题With a candle in hand, he carefully ______ the narrow stairs to his bedroom. A. asserted B. ascertained C. assembled D. ascended

单选题{{B}}Passage 3{{/B}} There are many good reasons for great current attention to university-industry relations, but there are troublesome reasons as well. One is that universities are now unusually hungry. There is nothing wrong with hunger. But a hungry man may cut comers in his rush to nourishment, and he may be taken advantage of in negotiations. Fear of this is leading to the threat of protectionism, as exemplified by recent attempts to classify or otherwise control access to university research, including that joint with industry. In designing university-industry connections, protecting interests by high-level negotiations is wrong. Protectionism is dangerous and habit-forming. Circumstances exist where it is appropriate, but only for a short time. One of the few essentials of agreements is that any secrecy or interference with open publication or student interaction should be strictly temporary. The dominant problem of supporting enough basic research in universities will remain. This must continue to be a federal responsibility; no company or industry can harvest the results soon enough to justify any investment larger than keeping a window on basic research and conduit for the movement of bright young people into the company. Hard work in the universities will lead to important cooperative research agreements with industry, but unremitting effort will be required to maintain or enlarge the basic research on which all else rests. But there is far more at stake than support for universities. University-industry interaction should not be looked upon as support at all, but as an absolutely necessary part of the survival both of American institutions and of the American economy. As the economy stumbles, protectionism of all kinds becomes rampant, and everyone loses. From the university's standpoint, cooperative projects with industry affect graduate (and even undergraduate) work in healthy ways. To use Harvey Brooks's phrase, giving students "respect for applied problems" is an important part of their education. Wisdom begins when students (and even professors) realize that an invention is not a product and a product is not an industry. What is perhaps most at stake is attracting some of the ablest young people to those fields that can make a difference in the survival of our society. Particle physics ought to be done, just as art galleries ought to be maintained, and the richer the country is the more particle physics and art galleries it should support. But it would be a disaster if protectionism, of either the government or the industry variety, were to discourage some of the best young people from going into applied fields.

单选题Not only the ______ are fooled by propaganda; we can all be misled if we are not wary.

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单选题In the past decade some third world countries have suffered from a cycle of drought ______ with flood.