Baseline Exam Is Key to Eye Health Even people with no signs or risk factors for eye disease can suffer vision loss and need to get baseline(基线)eye exams at age 40, says the American Academy of Ophthalmology(AAO)(美国眼科学会) The reminder(提示)is part of the AAO's EyeSmart campaign to mark Save Your Vision Month in February. " Many eye diseases progress without any warning signs, " Dr. Stephanie Marioneaux, a clinical correspondent for the AAO, said in a prepared statement. "Gradual changes in vision can affect your ability to function independently and have confidence in your abilities. Based on the findings from the initial screening, an eye doctor will create a schedule for follow-up eye exams. People of any age who have symptoms of eye disease or are at high risk due to family history, diabetes(糖尿病)or high blood pressure should consult with their eye doctor to determine how often they should have their eyes checked, the AAO recommends. By 2020, 43 million Americans will be at significant risk for vision loss or blindness due to age-related eve diseases such as cata-racts(白内障)and glaucoma(青光眼). That's a more than 50 percent increase over the current number of Americans with such vision-threatening diseases. But many Americans are unconcerned about the risk of vision loss. Only 23 percent of Americans are very concerned about losing their vision, while most feel weight gain or joint or back pain are greater worries than vision loss, according to an AAO survey conducted for its EyeSmart campaign.

Eating Potatoes Gives Your Immune System a Boost Eating potatoes is not only good for bowel health, but also for the whole immune system, especially when they come in the form of a potato salad or eaten cold. In a study on an animal model, researchers in Spain found that pigs fed large【C1】______of raw potato starch(RPS)not only had a healthier bowel, but also decreased levels of white blood cells,【C2】______as leucocytes and lymphocytes in their blood. White blood cells are produced as a【C3】______of inflammation or disease, generally when the body is challenged. The general down-regulation of leucocytes observed by the Spanish researchers suggests an overall beneficial effect, a generally more【C4】______body. The reduction in leucocyte levels was about 15 percent. Lower lymphocyte levels are also indicative of【C5】______levels of inflammation , but the observed reduction in both lymphocyte density【C6】______lymphocyte apoptosis is surprising. In 【C7】______was the longest study of its kind, pigs were fed RPS over 14 weeks to 【C8】______the effect of starch on bowel health. "The use of raw potato starch in this experiment is【C9】______to simulate the effects of a diet high in resistant starch," said study leader Jose Francisco Perez at the Universitat Autonoma de Barcelona, Spain. Humans do not eat【C10】______potatoes, but they do eat a lot of foods that contain resistant starch, such as cold boiled potatoes,legumes,grains,green bananas,pasta and cereals. About 10 percent of the starch eaten by human is resistant starch—starch that is not【C11】______in the small intestine and so is shunted into the large intestine where it ferments. Starch consumption is thought to reduce the【C12】______of large bowel cancer and may also have an effect on irritable bowel syndrome(IBS). Immunology expert Lena Ohman' s team【C13】______found that the overall lymphocyte levels do not vary for IBS patients,but that lymphocytes are transferred from the peripheral blood to the gut,which support the hypothesis of IBS being【C14】______least partially an inflammatory disorder. She says the decrease in lymphocytes observed by the Spanish is therefore interesting, and a diet of resistant starch may be worth【C15】______in IBS patients. Ohman is currently at the Department of Internal Medicine, Goteborg University, Sweden. The study is published in the Journal Chemistry and Industry, the magazine of the SCI.

The most crucial problem any economic system faces is how to use its scarce resources.

A infected body fluidsB against the outbreak severityC the mode of transmissionD the initial days of being infectedE three countries in West AfricaF within a wide range of days

The law carries a penalty of up to three years in prison.

The political situation in the region has deteriorated rapidly.

阅读理解Adaptation of Living Things Certain animals and plants develop characteristics that help them cope with their environment better than others of their kind. This natural biological process is called adaptation. Among the superior characteristics developed through adaptation are those that may help in getting food or shelter, in providing protection, and in producing and protecting the young. That results in the evolution of more and more organisms that are better fitted to their environments. Each living thing is adapted to its way of life in a general way, but each is adapted especially to its own distinct class. A plant, for example, depends upon its roots to fix itself firmly and to absorb water and inorganic chemicals. It depends upon its green leaves for using the sun''s energy to make food from inorganic chemicals. These are general adaptations, common to most plants. In addition, there are special adaptations that only certain kinds of plants have. Many animals have adaptations that help them escape from their enemies. Some insects are hidden by their body color or shape, and many look like a leaf or a little branch. The coats of deer are colored to mix with the surroundings. Many animals have the ability to remain completely still when an enemy is near. Organisms have a great variety of ways of adapting. They may adapt in their structure, function, and genetics; in their development and production of the young; and in other respects. An organism may create its won environment, as do warm-blooded mammals, which have the ability to adjust body heat exactly to maintain their ideal temperature despite changing weather. Usually adaptations are an advantage, but sometimes an organism is so well adapted to a particular environment that, if conditions change, it finds it difficult or impossible to readapt to the new conditions.

阅读理解On Antibodies Substances foreign to the body, such as disease-causing bacteria and viruses and other infectious agents, are recognized by the body s immune system as invaders. Our natural defenses against these infectious agents are antibodies, proteins that seek out the antigens (抗原) and help destroy them. Antibodies have two very useful characteristics. First, they are extremely specific; that is, each antibody binds to and attacks one particular antigen. Second, some antibodies, once activated by the occurrence of a disease, continue to confer resistance against that disease. Classic example are the antibodies to the childhood diseases of chickenpox(水痘) and measles. The second characteristic of antibodies makes it possible to develop vaccines. A vaccine (痘苗) is a preparation of killed or weakened bacteria or viruses that, when introduced into the body, stimulates the production of antibodies against the antigens it contains. It is the first trait of antibodies, their specificity, that makes monoclonal antibody technology so valuable. Not only can antibodies be used therapeutically(在治疗上), to protect against disease; they can also help to .diagnose a wide variety of illnesses, and can detect the presence of drugs, viral and bacterial products, and other unusual or abnormal substances in the blood. Given such a diversity of uses for these diseased-fighting substances, their production in pure quantities has long been the focus of scientific investigation. The conventional method was to inject a laboratory animal with an antigen and then, after antibodies had been formed, collect those antibodies from the blood serum(血清) (Antibody containing blood serum is called antiserum (抗血清)). There are two problems with this method: It yields antiserum that contains undesired substances, and it provides a very small amount of usable antibody. Monoclonal antibody technology allows us to produce large amounts of pure antibodies. in the following way: we can obtain cells that produce antibodies naturally; we also have available a class of cells that can grow continually in cell culture (培养). If we form a hybrid (混血儿) that combines the characteristic of "immortality"(永生)with the ability to produce the desired substance, we would have, in effect, a factory to produce antibodies that work around the clock. In monoclonal antibody technology, tumor cells that can replicate (重复) endlessly are fused with mammalian cells that produce an antibody. The result of this cell fusion is a "hybridoma" (杂交瘤), which will continually produce antibodies. These antibodies are called monoclonal because they come from only one type of cell, the hybridoma cell; antibodies produced by conventional methods, on the other hand, are derived from preparations containing many kinds of cells, and hence are called polyclonal. An example of how monoclonal antibodies are derived is described below. A myeloma is a tumor of the bone marrow (骨髓) that can be adapted to grow permanendy in cell culture. When myeloma cells were fused with antibody-producing mammalian spleen cells, it was found that the resulting hybrid cells, or hybridomas, produced large amounts of monoclonal(骨髓瘤) antibody. This product of cell fusion combined the desired qualities of the two different types of cells: the ability to grow continually, and the ability to produce large amounts of pure antibody. Because selected hybrid cells produce only one specific antibody, they are more pure than the polyclonal antibodies produced by conventional techniques. They are potentially more effective than conventional drugs in fighting disease, since drugs attack not only the foreign substance but the body’s own cells as well, sometimes producing undesirable side effects such as nausea(恶心) and allergic reactions. Monoclonal antibodies attack the target molecule and only the target molecule, with no or greatly diminished side effects.

阅读理解Cigars Instead? Smoking one or two cigars a day doubles the risk of cancers of the lip, tongue, mouth, and throat, according to a government study. Daily cigars also increase the risk of lung cancer and cancer of the esophagus, and increase the risk of cancer of the larynx (voicebox) sixfold, say researchers at the National Cancer Institute in Bethesda, Maryland. In addition, the report revealed that smoking three or four cigars a day increased the risk of oral cancer to 8.5 times the risk for nonsmokers and the risk of esophageal cancer by four times the risk of nonsmokers. The health effects of smoking cigars is one of eight sections of the article " Cigars: Health Effects and Trends". The researchers report that, compared with a cigarette, a large cigar emits up to 90 times as much carcinogenic tobacco-specific nitrosamines "This article provides clear and invaluable information about the disturbing increase in cigar use and the significant public health consequences for the country," said Dr. Richard Klausner, director of the National Cancer Institute, in a statement. "The data are clear-the harmful substances and carcinogens in cigar smoke, like cigarettes, are associated with the increased risks of several kinds of cancers as well as heart and lung diseases," he added. " In other words, cigars are not safe alternatives to cigarettes and may be addictive. " "To those individuals who may be thinking about smoking cigars, our advices is — don''t. To those currently smoking cigars, quitting is the only way to eliminate completely the cancer, heart and lung disease risks," warned Klausner. According to a National Cancer Institute press release, there haven''t been any studies on the health effects on nonsmokers at cigar social events, but "... a significant body of evidence clearly demonstrates an increased lung cancer risk from secondhand smoke. "

阅读理解Most Adults in U. S. Have Low Risk of Heart Disease More than 80 percent of US adults have a less than 10 percent risk of developing heart disease in the next 10 years, according to a report in the Journal of the American College of Cardiology. Just 3 percent have a risk that exceeds 20 percent. "I hope that these numbers will give physicians, researchers, health policy analysts, and others a better idea of how coronary heart disease is distributed in the US population, " lead author Dr. Earl S. Ford, from the Centers for Disease Control and Prevention in Atlanta, said in a statement. The findings are based on analysis of data from 13,769 subjects, between 20 and 79 years of age, who participated in the Third National Health and Nutrition Examination Survey from 1988 to 1994. Overall, 82 percent of adults had a risk of less than 10 percent, 15 percent had a risk that fell between 10 to 20 percent, and 3 percent had a risk above 20 percent. The proportion of subjects in the highest risk group increased with advancing age, and men were more likely than women to be in this group. By contrast, race or ethnicity had little effect on risk distributions. Although the report suggests that most adults have a low 10-year risk of heart disease, a large proportion have a high or immediate risk, Dr. Daniel S. Berman, from Cedars-Sinai Medical Center in Los Angeles, and Dr. Nathan D. Wong, from the University of California at Irvine, note in a related editorial. Aggressive treatment measures and public health strategies are needed to shift the overall population risk downward, they add.

阅读理解Architecture Architecture is to building as literature is to the printed word. ''The best buildings ate often so well constructed that they outlast their original use. They then survive not only as beautiful objects, but as documents of the history of cultures. These achievements are never wholly the work of individuals. Architecture is a social art. The renaissance brought about an entirely new age, not only in philosophy and literature but in the visual arts as well. In architecture, the principles and styles of ancient Greece and Rome were brought back to life and reinterpreted. They remain dominant until the 20th century. Many kinds of stone are used as building materials. Stone and marble were chosen for important monuments because they are not burnable and Can be expected to endure. Stone architecture was often blended with stone sculpture. The use of stone has declined, however, because a number of other materials ate more adaptable to industrial use. The complexity of modem lire calls for a variety of buildings. More people live in mass housing and go to work in large office buildings; they spend their income in large shopping centers, send their children to many different kinds of schools, and when they ate sick they go to specialized hospitals and clinics. All these different types of buildings accumulated experiences needed by their designers. By the middle of the 20th century, modem architecture, which was influenced by new technology and mass production, was dealing with increasingly complex social needs. Important characteristics of modem architectural works are expanses of glass and the use of reinforced concrete. Advances in elevator technology, air conditioning, and electric lighting have all had important effects. A. Building Materials B. Need of Greater Building Varieties in Modern Life C. Restoration of Ancient Civilizations D. Evolution in Style E. Factors Affecting Modem Architectur 6 F. A Social Art

单选题Preserving Nature for Future Demands for stronger protection for wildlife in Britain sometimes hide the fact that similar needs are felt in the rest of Europe. Studies by the Council of Europe, of which 21 countries are members, have shown that 45 per cent of reptile (爬行动物) species and 24 per cent of butterflies (蝴蝶) are in danger of dying out. European concern for wildlife was outlined by Dr. Peter Baum, an expert in the environment and natural resources division of the council, when he spoke at a conference arranged by the administrators of a British national park. The park is one of the few areas in Europe to hold the council"s diploma (证书) for nature reserves (自然保护区) of me highest quality, and Dr. Baum had come to present it to the park once again. He was afraid that public opinion was turning against national parks, and that those set up in the 1960s and 1970s could not be set up today. But Dr. Baum clearly remained a strong supporter of the view that natural environments needed. To be allowed to survive in peace in their own right. "No area could be expected to survive both as a true nature reserve and as a tourist attraction." he went on. The short, sighted view that reserves had to serve immediate human demands for outdoor recreation (户外娱乐) should be replaced by full acceptance of their importance as places to preserve nature for the future. "We forget that they are the guarantee of life systems, on which any built-up area ultimately depends." Dr. Baum went on. "We could manage without most industrial products, but we could not manage without nature. However, our natural environment areas, which are the original parts of our countryside, have shrunk (缩小) to become mere islands in a spoiled and highly polluted landmass."

单选题It is no use debating the relative merits of this policy.

单选题The news will Uhorrify /U everyone.

单选题This original model was designed to interface easily with test and measurement instruments.A. interactB. provideC. connectD. work

单选题{{B}}第二篇{{/B}} {{B}} Supermarket{{/B}} Most supermarkets need a very large floor area, sometimes at least ten times as big as that of an ordinary shop. There are usually two doors, one as an entrance and the other as an exit. The rest of the side facing the street is largely of plate glass, with goods or advertising material displayed. The other three walls are normally decorated in light colours, giving an impression of cleanliness (清洁)and brightness. Most supermarkets are on one floor only. Goods being stored in rooms at the back or upstairs. At right-angles to the window stretch long structures about six feet high with a number of shelves on each side. Similar shelf units or frozen food containers extend round the walls. Broad aisles(通道)between the shelf units and ample(足够的)space between them and the window and also the far wall allow room for the circulation of many people. Individual commodities(商品), in tins, bags, boxes or other containers, are stacked (堆放) in groups on the shelves, and each group is labelled with a price ticket. Metal baskets near the entrance are taken by the shoppers who collect in them the goods they select from the shelves. Between the shelf units and the window in one half of the shops are a number of small counters about three feet high. Beside each sits a cashier (现金出纳员), who operates a machine for reckoning, detailing the cost of each customer's purchases. The customer places the basket at one end of the counter so that it can be emptied by the cashier who records the price of the commodities one by one, before putting each on a moving section of the counter top. The goods are collected and packed into the customer's bag by another assistant at the end of the counter. The cashier finally hands a printed slip recording all prices to the customer, who pays the total, collects the bag and leaves.

单选题How many diagnosed diabetes patients are there in Britain?

单选题Hypnosis is not effective in treating cigarette smokers and persons who eat or drink too much is because______

单选题They have given up the hope to save their friend from drowning.

单选题Fine freshwater pearls are found in the main stream and the {{U}}tributaries{{/U}} of the Mississippi River. A. banks B. deltas C. branches D. currents