单选题The distance between the earth and the sun may be said to be ______.

单选题How does the author contrast aristocratic and democratic societies in their response to religion?

单选题Stocks are not goods--they merely are ______, exchanging current cash flows for future ones. A. conducts B. conduction C. conduits D. products

单选题In the second paragraph, why is the word "greater" in italics?

单选题An outbreak of swine flu outside of Mexico City was Ublamed for/U the deaths of more than a hundred people in April 2009.

单选题Ground-level ozone is an air pollutant that causes human health problems even at very low levels. It also damages crops and other vegetation. It is a key ingredient of urban smog. "Good ozone" occurs naturally in the stratosphere approximately 10 to 30 miles above the earth's surface and forms a layer that protects life on earth from the sun's harmful rays. "Bad ozone" is formed in the earth's lower atmosphere, near ground level, when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources react chemically in the present of sunlight. Ozone pollution is a concern during the summer months when the weather conditions needed to form ground-level ozone — lots of sun, hot temperatures — normally occur. The length of ozone season varies from one area of the United States to another. Southern and southwestern states may have an ozone season that lasts nearly the entire year. Ozone can irritate lung airways and cause inflammation much like sunburn. Other symptoms include wheezing, coughing, pain when taking it deep breath, and breathing difficulties during exercise of outdoor activities. People with respiratory problems are most vulnerable, but even healthy people who are active outdoors can be affected when ozone levels are high. Repeated exposure to ozone pollution for several months may cause permanent lung damage. Anyone who spends time outdoors in the summer is at risk, particularly children and other people who are active outdoors. Even at very low levels, ground-level ozone triggers a variety of problems including aggravated asthma, reduced lung capacity, and increased susceptibility to respiratory illnesses like pneumonia and bronchitis. Ozone damage can occur without any noticeable signs. People who love in areas where ozone levels are frequently high may find that their initial symptoms go away overt time — particularly when exposure to high ozone levels continues for several days. Ozone continues to cause lung damage even when the symptoms have disappeared.

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单选题The prisoner ______ that he had assaulted a policeman. A.refused B.denied C.rejected D.declined

单选题Forget football. At many high schools, the fiercest competition is between Coke and Pepsi over exclusive "pouring rights" to sell on campus. But last week Jeffrey Dunn, president of Coca-Cola Americas, called a timeout: Coke's machines will now also stock water, juice, and other healthful options—even rival brands and their facades will feature school scenes and other "noncommercial graphics" instead of Coke's vivid red logo. "The pendulum needs to swing back" on school-based marketing, said Dunn. Coke's about-face—particularly the call to end the exclusive deals that bottlers make with school districts—comes amid rising concern over kids' health. American children are growing ever more obese and developing weight-related diseases usually found in adults. While inactivity and huge helpings factor heavily, a recent study in the Lancet fingered soda pop as a likely culprit. Communities—and legislators—are already on the case. Last year, for instance, parents in Philadelphia detailed a proposed contract with Coca-Cola that would have netted the school system $43 million over 10 years. And in a searing report to Congress last month, the U. S. Department of Agriculture recommended that all snacks sold in schools meet federal nutrition standards (the requirements are loose enough that Snickers bars qualify), Spare change? Activists hope Coke's capitulation will help curb commercialism in schools altogether. From ads on Channel One, which broadcasts current-affairs programs on classroom TVs, to middle-school math texts that cite Nike and other brand-name products in their word problems, to company-sponsored scoreboards on football fields, American pupils are bombarded. But Andrew Hagelshaw, executive director of the Oakland, Calif.-based Center for Commercial-Free Public Education, views Coca-Cola's policy shift as a "partial victory". Schools sign contracts with local bottlers; the parent company can only urge them to back off. Moreover, Coke's machines will remain in place, although with healthier options. And don't expect teenagers to suddenly swear off the stuff—or school districts to give up the revenue. At Wheeler High School in Marietta, Ga., where students arrive before 7 a. m. and stay as late as 11 o'clock at night, they rely on the machines. And the $50, 000 in annual vending revenues have enabled Principal Joe Boland to refinish the gym floor, install a new high-jump pit, and pay $7, 000 for two buses. "If someone made an offer to me to take the machines out, I'd consider it," says Boland. "But nobody's offering me any money./

单选题There could have been a war over it but peace ______ in the end.

单选题No ______is given at this shop; payment must be in cash,

单选题The politician tried to convince the voters that he was the man for the job.

单选题Left in the garage where it was damp, the wooden frame had______. A. tingled B. sizzled C. swindled D. warped

单选题He added a ______ to his letter by saying that he would arrive before 8 pm.

单选题Is language, like food, a basic human need without which a child at a critical period of life can be starved and damaged? Judging from the drastic experiment of Frederick I in the thirteenth century, it may be hoping to discover what language a child would speak if he heard no mother tongue, he told the nurses to keep silent. All the infants died before the first year. But clearly there was more than lack of language here What was missing was good mothering. Without good mothering, in the first year of life especially, the capacity to survive is seriously affected. Today no such severe lack exists as that ordered by Frederick. Nevertheless, some children are still backward in speaking. Most often the reason for this is that the mother is insensitive to the signals of the infant, whose brain is programmed to learn language rapidly. If these sensitive periods are neglected, the ideal time for acquiring skills passes and they might never be learned so easily again. A bird learns to sing and to fly rapidly at right time, but the process is slow and hard once the critical stage has passed. Experts suggest that speech stages are reached in a fixed sequence and at a constant age, but there are cases where speech has started late in a child who eventually turns out to be of high IQ. At twelve weeks a baby smiles and makes bowel-like sounds; at twelve months he can speak simple words and understand simple commands; at eighteen months he has a vocabulary of three to fifty words. At three he knows about 1,000 words which he can put into sentences, and at four his language differs from that of his parents in born with the capacity to speak. What is special about man"s brain, compared with that of the monkey, is the complex system which enables a child to connect the sight and feel of, say, a toy-bear with the sound pattern "toy-bear". And even more incredible is the young brain"s ability to pick out an order in language from the mixture of sound around him, to analyze, to combine and recombine the parts of a language in new ways. But speech has to be induced, and this depends on interaction between the mother and the child, where the mother recognizes the signals in the child"s babbling, grasping and smiling, and responds to them. Insensitivity of the mother to these signals dulls the interaction because the child gets discouraged and sends out only the obvious signals. Sensitivity to the child"s non-verbal signals is essential to the growth and development of language.

单选题At first, movies were little more than amusing______that appeared to move. A. novels B. novelties C. notices D. novices

单选题It is often difficult to ______ between a mere exaggeration and a deliberately. (2006年中国矿业大学考博试题)

单选题 The antigen-antibody immunological reaction used to be regarded as typical of immunological responses. Antibodies are proteins synthesized by specialized cells called plasma cells, which are funned by lymphocytes (cells from the lymph system} when an antigen, a substance foreign to the organism's body, comes in contact with lymphocytes. Two important manifestations of antigen- antibody immunity are lysis, the rapid physical rupture of antigenic cells and the liberation of their contents into the surrounding medium, and phagocytosis, a process in which antigenic particles are engulfed by and very often digested by macrophages and polymorphs. The process of lysis is executed by a complex and unstable blood constituent known as complement, which will not work unless it is activated by a specific antibody; the process of pbagocytosis is greatly facilitated when the particles to be engulfed are coated by a specific antibody directed against them. The reluctance to abandon this hypothesis, however well it explains specific processes, impeded new research, and for many years antigens and antibodies dominated the thoughts of immunologists so completely that those immunologists overlooked certain difficulties. Perhaps the primary difficulty with the antigen-antibody explanation is the informational problem of how an antigen is recognized and how a structure exactly complementary to it is then synthesized. When molecular biologists discovered, moreover, that such information cannot flow from protein to protein, hut only from nucleic acid to protein, the theory that an antigen itself provided the mold that directed the synthesis of an antibody had to be seriously qualified. The attempts at qualification and the information provided by research in molecular biology led scientists to realize that a second immunological reaction is mediated through the lymphocytes that are hostile to and bring about the destruction of the antigen. This type of immunological response is called cell- mediated immunity. Recent research in cell-mediated immunity has been concerned not only with the development of new and better vaccines, but also with the problem of transplanting tissues and organs from one organism to another, for although circulating antibodies play a part in the rejection of transplanted tissues, the primary role is played by cell-mediated reactions. During cell-mediated responses, receptor sites on specific lymphoeytes and surface antigens on the foreign tissue cells form a complex that binds the lymphocytes to the tissue. Such lymphocytes do not give rise to antibody- producing plasma cells but themselves bring about the death of the foreign-tissue cells, probably by secreting a variety of substances, some of which are toxic to the tissue cells and some of which stimulate increased phagocyte activity by white blood cells of the macrophage type. Cell-mediated immunity also accounts for the destruction of intracellular parasites.

单选题The United States Food and Drag Administration has shown itself to be particularly {{U}}wary{{/U}} with regard to alleged "miracle" drugs in recent times.

单选题The crowd Uswelled/U in the evening until the noise made by the crowd could be heard for miles.