四级快速阅读指导练习.doc

四级快速阅读指导练习环保类Will We Run Out of Water?Picture a “ghost ship” sinking into the sand, left to rot on dry land by a receding sea. Then imagine dust storms sweeping up toxic pesticides and chemical fertilizers from the dry seabed and spewing them across towns and villages.Seem like a scene from a movie about the end of the world? For people living near the Aral sea (咸海) in Central Asia, its all too real. Thirty years ago, government planners diverted the rivers that flow into the sea in order to irrigate (provide water for ) farmland. As a result, the sea has shrunk to half its original size, stranding (使搁浅) ships on dry land. The seawater has tripled in salt content and become polluted, killing all 24 native species of fish.Similar large-scale efforts to redirect water in other parts of the world have also ended in ecological crisis, according to numerous environmental groups. But many countries continue to build massive dams and irrigation systems, even though such projects can create more problems than they fix. Why? People in many parts of the world are desperate for water, and more people will need more water in the next century.“Growing populations will worsen problems with water,” says Peter H.Gleick, an environmental scientist at the Pacific Institute for studies in Development, Environment, and Security, a research organization in California. He fears that by the year 2025, as many as one-third of the worlds projected (预测的) 8.3 billion people will suffer from water shortages.WHERE WATER GOESOnly 2.5 percent of all water on Earth is freshwater, water suitable for drinking and growing food, says Sandra Postel, director of the Global Water Policy Project in Amherst, Mass. Two-thirds of this freshwater is locked in glaciers (冰山) and ice caps （冰盖）. In fact, only a tiny percentage of freshwater is part of the water cycle, in which water evaporates and rises into the atmosphere, then condenses and falls back to Earth as precipitation (rain or snow).Some precipitation runs off land to lakes and oceans, and some becomes groundwater, water that seeps into the earth. Much of this renewable freshwater ends up in remote places like the Amazon river basin in Brazil, where few people live. In fact, the worlds population has access to only 12,500 cubic kilometers of freshwaterabout the amount of water in Lake Superior(苏必利尔湖). And people use half of this amount already. “If water demand continues to climb rapidly,” says Postel, “there will be severe shortages and damage to the aquatic (水的) environment.”CLOSE TO HOMEWater woes(灾难) may seem remote to people living in rich countries like the United States. But Americans could face serious water shortages, too especially in areas that rely on groundwater. Groundwater accumulates in aquifers (地下蓄水层)，layers of sand and gravel that lie between soil and bedrock. (For every liter of surface water, more than 90 liters are hidden underground.) Although the United States has large aquifers, farmers, ranchers, and cities are tapping many of them for water faster than nature can replenish(补充) it. In northwest Texas, for example, overpumping has shrunk groundwater supplies by 25 percent, according to Postel.Americans may face even more urgent problems from pollution. Drinking water in the United States is generally safe and meets high standards. Nevertheless, one in five Americans every day unknowingly drinks tap water contaminated with bacteria and chemical wastes, according to the Environmental Protection Agency. In Milwaukee, 400,000 people fell ill in 1993 after drinking tap water tainted with cryptosporidium (隐孢子虫)，a microbe (微生物) that causes fever, diarrhea (腹泻) and vomiting.THE SOURCEWhere so contaminants come from? In developing countries, people dump raw (未经处理的) sewage(污水) into the same streams and rivers from which they draw water for drinking and cooking; about 250 million people a year get sick from water borne (饮水传染的) diseases.In developed countries, manufacturers use 100,000 chemical compounds to make a wide range of products.Toxic chemicals pollute water when released untreated into rivers and lakes. (Certain compounds, such as polychlorinated biphenyls (多氯化联二苯)，or PCBs, have been banned in the United States.)But almost everyone contributes to water pollution. People often pour household cleaners, car antifreeze, and paint thinners (稀释剂) down the drain; all of these contain hazardous chemicals. Scientists studying water in the San Francisco Bay reported in 1996 that 70 percent of the pollutants could be traced to household waste.Farmers have been criticized for overusing herbicides and pesticides, chemicals that kill weeds and insects but insects but that pollute water as well. Farmers also use nitrates, nitrogen-rich fertilizer that helps plants grow but that can wreak havoc (大破坏) on the environment. Nitrates are swept away by surface runoff to lakes and seas. Too many nitrates “overenrich” these bodies of water, encouraging the buildup of algae, or microscopic plants that live on the surface of the water. Algae deprive the water of oxygen that fish need to survive, at times choking off life in an entire body of water.WHATS THE SOLUTION?Water expert Gleick advocates conservation and local solutions to water-related problems; governments, for instance, would be better off building small-scale dams rather than huge and disruptive projects like the one that ruined the Aral Sea.“More than 1 billion people worldwide dont have access to basic clean drinking water,” says Gleick. “There has to be a strong push on the part of everyonegovernments and ordinary peopleto make sure we have a resource so fundamental to life.”提示:在实考试卷中，8-10题在答题卡1上。1. That the huge water projects have diverted the rivers causes the Aral Sea to shrink.2. The construction of massive dams and irrigation projects does more good than harm.3. The chief causes of water shortage are population growth and water pollution.4. The problems Americans face concerning water are ground water shrinkage and tap water pollution.5. According to the passage all water pollutants come from household waste.6. The people living in the United States will not be faced with water shortages.7. Water expert Gleick has come up with the best solution to waterrelated problems.8. According to Peter H. Gleick, by the year 2025, as many as _of the worlds people will suffer from water shortages.9. Twothirds of the freshwater on Earth is locked in _.10. In developed countries, before toxic chemicals are released into rivers and lakes, they should be treated in order to avoid _. 教育类Early Childhood EducationEducation To Be More was published last August. It was the report of the New ZealandGovernments Early Childhood Care and Education Working Group. The report argued for enhanced equity (公平) of access and better funding for childcare and early childhood education institutions. Unquestionably, thats a real need but since parents dont normally send children to preschools until the age of three, are we missing out on the most important years of all?A 13year study of early childhood development at Harvard University has shown that, by the age of three, most children have the potential to understand about 1000 words most of the language they will use in ordinary conversation for the rest of their lives.Furthermore, research has shown that while every child is born with a natural curiosity, it can be suppressed dramatically during the second and third years of life. Researchers claim that the human personality is formed during the first two years of life, and during the first three years children learn the basic skills they will use in all their later learning both at home and at school.Once over the age of three, children continue to expand on existing knowledge of the world. It is generally acknowledged that young people from poorer socioeconomic backgrounds tend to do less well in our education system. Thats observed not just in New Zealand, but also in Australia, Britain and America. In an attempt to overcome that educational underachievement,anationwide program called Headstart was launched in the United States in 1965. A lot of money was poured into it. It took children into preschool institutions at the age of three and was supposed to help the children of poorer families succeed in school.Despite substantial funding, results have been disappointing. It is thought that there are two explanations for this. First, the program began too late. Many children who entered it at the age of three were already behind their peers in language and measurable intelligence. Second, the parents were not involved. At the end of each day, Headstart children returned to the same disadvantaged home environment.As a result of the growing research evidence of the importance of the first three years of a childs life and the disappointing results from Headstart, a pilot program was launched in Missouri in the US that focused on parents as the childs first teachers. The Missouri program was predicated on research showing that working with the family, rather than bypassing the parents, is the most effective way of helping children get off to the best possible start in life. The fouryear pilot study included 380 families who were about to have their first child and who represented a crosssection of socioeconomic status, age and family configurations (结构). They included singleparent and twoparent families, families in which both parents worked, and families with either the mother or father at home. The program involved trained parent educators visiting the parents home and working with the parent, or parents, and the child. Information on child development, and guidance on things to look for and expect as the child grows were provided, plus guidance in fostering the childs intellectual, language, social and motorskill development. Periodic checkups of the childs educational and sensory development (hearing and vision) were made to detect possible handicaps that interfere with growth and development. Medical problems were referred to professionals.Parenteducators made personal visits to homes and monthly group meetings were held with other new parents to share experience and discuss topics of interest. Parent resource centers, located in school buildings, offered learning materials for families and facilities for child.At the age of three, the children who had been involved in the Missouri program were evaluated alongside a crosssection of children selected from the same range of socioeconomic backgrounds and family situations, and also a random sample of children that age. The results were phenomenal. By the age of three, the children in the program were significantly more advanced in language development than their peers, had made greater strides in problem solving and other intellectual skills, and were further along in social development. In fact, the average child on the program was performing at the level of the top 15 to 20 per cent of their peers in such things as auditory comprehension, verbal ability and language ability.Most important of all, the traditional measures of risk, such as parents age and education, or whether they were a single parent, bore little or no relationship to the measures of achievement and language development. Children in the program performed equally well regardless of socioeconomic disadvantages. Child abuse was virtually eliminated. The one factor that was found to affect the childs development was family stress leading to a poor quality of parentchild interaction. That interaction was not necessarily bad in poorer families.These research findings are exciting. There is growing evidence in New Zealand that children from poorer socioeconomic backgrounds are arriving at school less well developed and that our school system tends to perpetuate (使永存) that disadvantage. The initiative outlined above could break that cycle of disadvantage. The concept of working with parents in their homes, or at their place of work, contrasts quite markedly with the report of the Early Childhood Care and Education Working Group. Their focus is on getting children and mothers access to childcare and institutionalized early childhood education. Education from the age of three to five is undoubtedly vital, but without a similar focus on parent education and on the vital importance of the first three years, some evidence indicates that it will not be enough to overcome educational inequity.1. The skills learned by children at age of three will be used in all their later learning in life.2. The Headstart program finally succeeded in its aim.3. The Missour program supplied many forms of support and training to parents.4. Most Missouri program threeyearolds scored highly in areas such as listening, speaking, reasoning and interacting with others.5. Missouri program children of young, uneducated, single parents scored less highly on the tests.6. The richer families in the Missouri program had higher stress levels.7. Educational inequity cannot be overcome for children from different family backgrounds.8. The aim of Headstart program is to help children from poor families overcome _.9. The most effective way of helping children get off to the best possible start in life is _.10. The concept of working with parents in their homes contrasts quite markedly with the report of the Early Childhood Core and _.科技类How Infectious Diseases WorkThe human body is both surrounded and inhabited by billions of microorganisms. Most microorganisms are harmless or even beneficial; for example, bacteria that normally live in the digestive system help digest food. Occasionally, however, a microorganism capable of causing a disease invades the body. Diseases caused by such microorganisms are called infectious diseases.Infectious diseases are contagious; that is, they can be passed from one person to another. They can be transmitted by skin contact, through body fluids, in contaminated food or drink, or via airborne particles containing the microorganisms, although the pathways and ease of transmission vary by disease.Animal or insect bites are another means of transmission. The two most common types of infectious diseases are bacterial infections and viral infections.Disease-causing, or pathogenic, bacteria either attack the bodys tissues directly or cause damage by secreting poisonous substances called toxins. Fortunately, bacterial infections are often curable. Certain bacteria can be killed by drugs; other bacterial diseases can be prevented by vaccination.Viruses are the smallest known microorganisms. They are responsible for diseases as relatively harmless as the common cold and as serious as meningitis. Viruses live and reproduce only within living cells, and only certain cells are susceptible to a specific virus. You can be host to many viruses without suffering any adverse effects, but if enough cells are attacked, you will become sick.There is no effective medical treatment for most viral infections. Because a virus lives inside a cell, any treatment designed to kill the virus is also likely to harm the cell. In addition, there are thousands of different viruseseach one with different propertiesand an agent effective against one virus probably will not affect the others. Although there are vaccinations to protect against some viral diseases, therapy for most viral diseases is limited to treating the symptoms.In this article, well focus on the many facets of infectious diseases, starting with how the body defends against them.The Bodys DefensesDespite the prevalence of disease-causing microorganisms, the body is not defenseless against these invaders. The body fights infections in three ways: by preventing the organisms from entering the body, by attacking those that do manage to enter, and by inactivating those organisms it cannot kill.Sometimes, too, the body fights disease by developing defensive symptoms. Fever is an example. During an illness, the bodys temperature regulator may respond to the illness by raising the bodys temperature. Some researchers believe that this is an effective response because the microorganisms causing the disease may not be able to survive the higher body temperature.The skin is the first barrier that guards the underlying tissues of the body. Where there are natural openings in the skin, there are also defenses. For example, tear glands in the eyes secrete and bathe the eyes with fluid that contains bacteria-fighting components. The salivary glands in the mouth and the tonsils in the throat help prevent microorganisms from attacking the mouth and throat.Many openings, as well as internal passages, in the body are lined with mucous membranes. These delicate layers produce mucus, a slippery secretion that moistens and protects by repelling or trapping microorganisms.Internally, certain body organs fight infection. For instance, the liver and the spleen (a large glandlike organ located in the abdomen) filter out harmful substances from the blood flowing through them. The lining of the stomach produces acids that attack germs in food that has been eaten. The bodys lymph system manufactures white blood cells, which attack and kill invading organisms.Now lets get even more specific in our look at the bodys defenses. Well start by describing the lymph system.The Lymph SystemThe lymph system is a network of vessels that carry lymph, a watery fluid containing white blood cells, throughout the body. Lymph drains from the blood vessels and body tissues, carrying away waste products. The waste products are filtered out of the lymph by small structures called lymph