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A controversy erupted in the scientific community in early 1998 over the use of DNA (deoxyribonucleic acid ) fingerprinting in criminal investigations. DNA fingerprinting was introduced in 1987 as a method to identify individuals based on a pattern seen in their DNA, the molecule of which genes are made. DNA is present in every cell of the body except red blood cells. DNA fingerprinting has been used successfully in various ways, such as to determine paternity where it is not clear who the father of a particular child is. However, it is in the area of criminal investigations that DNA fingerprinting has potentially powerful and controversial uses.DNA fingerprinting and other DNA analysis techniques have revolutionized criminal investigations by giving investigators powerful new tools in the attempt to trove guilt, not just establish innocence. When used in criminal investigations, a DNA fingerprint pattern from a suspect is compared with a DNA fingerprint pattern obtained from such material as hairs or blood found at the scene of a crime. A match between the two DNA samples can be used as evidence to convict a suspect.The controversy in 1998 stemmed form a report published in December 1991 by population geneticists Richard C. Lewontin of Harvard University in Cambridge, Mass., and Daniel L. Hartl called into question the methods to calculate how likely it is that a match between two DNA fingerprints might occur by chance alone. In particular, they argued that the current method cannot properly determine the likelihood that two DNA samples will match because they came from the same individual rather than simply from two different individuals who are members of the same ethnic group. Lewontin and Hartl called for better surveys of DNA patterns methods are adequate.In response to their criticisms, population geneticists Ranajit Chakraborty of the University of Texas in Dallas and Kenneth K.Kidd of Yale University in New Haven, Conn., argued that enough data are already available to show that the methods currently being used are adequate. In January 1998, however, the federal Bureau of Investigation and laboratories that conduct DNA tests announced that they would collect additional DNA samples form various ethnic groups in an attempt to resolve some of these questions. And, in April, a National Academy of Sciences called for strict standards and system of accreditation for DNA testing laboratories.1.Before DNA fingerprinting is used, suspects____.A.would have to leave their fingerprints for further investigationsB.would have to submit evidence for their innocenceC.could easily escape conviction of guiltD.cold be convicted of guilt as well2.DNA fingerprinting can be unreliable when ____.A.the methods used for blood- cell calculation are not accurateB.two different individuals of the same ethnic group may have the same DNA fingerprinting patternC.a match is by chance left with fingerprints that happen to belong to two different individualsD.two different individuals leave two DNA samples.3.To geneticists like Lewontin and Hartl, the current method ____.A.is not so convincing as to exclude the likelihood that two DNA samples can never come from two individualsB.is arguable because two individuals of the same ethnic group are likely to have the same DNA pattern.C.Is not based on adequate scientific theory of geneticsD.Is theoretically contradictory to what they have been studying4.The attitude of the Federal Bereau of Investigation shows that ____.A.enough data are yet to be collected form various ethnic groups to confirm the unlikelihood of two DNA samples coming from two individual membersB.enough data of DNA samples should be collected to confirm that only DNA samples form the same person can matchC.enough data are yet to be collected from various ethnicgroups to determine the likelihood of two different DNA samples coming form the same personD.additional samples from various ethnic groups should be collected to determine that two DNA samples are unlikely to come from the same person5.National Academy of Sciences holds the stance that ____.A.DNA testing should be systematizedB.Only authorized laboratories can conduct DNA testingC.The academy only is authorized to work out standards for testingD.The academy has the right to accredit laboratories for DNA testing参考答案：CBABBWe can begin our discussion of “population as global issue” with what most persons mean when they discuss “the population problem”: too many people on earth and a too rapid increase in the number added each year. The facts are not in dispute, It was quite right to employ the analogy that likened demographic growth to “a long, thin powde r fuse that burns steadily and haltingly until it finally reaches the charge and explodes.”To understand the current situation, which is characterized by rapid increases in population, it is necessary to understand the history of population trends. Rapid growth is a comparatively recent phenomenon. Looking back at the 8,000 years of demographic history, we find that populations have been virtually stable or growing very slightly for most of human history. For most of our ancestors, life was hard, often nasty, and very short. There was high fertility in most places, but this was usually balanced by high mortality. For most of human history, it was seldom the case that one in ten persons would live past forty, while infancy and childhood were especially risky periods. Often,societies were in clear danger of extinction because death rates could exceed their birthrates. Thus, the population problem throughout most of history was how to prevent extinction of the human race.This pattern is important to notice. Not only does it put the current problems of demographic growth into a historical perspective, but it suggests that the cause of rapid increase in population in recent years is not a sudden enthusiasm for more children, but an improvement in the conditions that traditionally have caused high mortality. Demographic history can be divided into two major periods: a time of long, slow growth which extended from about 8,000 BC.till approximately AD. 1650. In the first period of some 9600 years, the population increased from some 8 million to 500 million in 1650. Between 1650 and the present, the population has increased from 500 million to more than 4 billion. And it is estimated that by the year 2000 there will be 6.2 billion people throughout the world. One way to appreciate this dramatic difference in such abstract numbers is to reduce the time frame to something that is more manageable. Between 8000BC and 1650, an average of only 50,000 persons was being added annually to the world’s population each year. At present, this number is added every six hours. The increase is about 80,000,000 persons annually.1.Which of the following demographic growth pattern is most suitable for the long thin powder fuse analogy?A.A virtually stable or slightly decreasing period and then a sudden explosion of population.B.A slow growth for a long time and then a period of rapid, dramatic increase.C.Too many people on earth and a few rapid increase in the number added each year.D.A long period when death rates exceeds birthrates and then a short period with higher fertility and lower mortality.2.During the first period of demographic history, societies were often in danger of extinction because___.A.only one in ten persons could live past 40.B.there was higher mortality than fertility in most places.C.it was too dangerous to have babies due to the poor conditions.D.our ancestors had little enthusiasm for more children.3.Which statement is true about population increase?A.There might be an increase of 2.2 billion persons from now to the year 2000.B.About 50,000 babies are born every six hours at present.C.Between 8000 BC and the present, the population increase is about 80,000,000 persons each year.D.The population increased faster between 8000BC and 1650 than between 1650 and the present.4.The author of the passage intends to___.A.warn people against the population explosion in the near future.pare the demographic growth pattern in the past with that after 1650.C.find out the cause for rapid increase in population in recent years.D.present us a clear and complete picture of the demographic growth.5.The word “demographic” in the first paragraph means___.A.statistics of human.B.surroundings study.C.accumulation of human.D.development of human.答案：ABADANot too m any decades ago it seemed “obvious” both to the general public and to sociologists that modern society has changed people’s natural relations, loosened their responsibilities to kin（亲戚）and neighbors, and substituted in their place superficial relationships with passing acquaintances. However, in recent years a growing body of research has revealed that the “obvious” is not true. It se ems that if you are a city resident, you typically know a smaller proportion of your neighbors than you do if you are a resident of a smaller community. But, for the most part, this fact has few significant consequences. It does not necessarily follow that if you know few of your neighbors you will know no one else.Even in very large cities, people maintain close social ties within small, private social worlds. Indeed, the number and quality of meaningful relationships do not differ between more and less urban people. Small-town residents are more involved with kin than are big-city residents. Yet city dwellers compensate by developing friendships with people who share similar interests and activities. Urbanism may produce a different style of life, but the quality of life does not differ between town and city. Nor are residents of large communities any likelier to display psychological symptoms of stress or alienation, a feeling of not belonging, than are residents of smaller communities. However, city dwellers do worry more about crime, and this leads them to a distrust of strangers.These findings do not imply that urbanism makes little or no difference. If neighbors are strangers to one another, they are less likely to sweep the sidewalk of an elderly couple living next door or keep an eye out for young trouble makers. Moreover, as Wirth suggested, there may be a link between a community’s population size and its social heterogeneity(多样性). For instance, sociologists have found much evidence that the size of a community is associated with bad behavior including gambling, drugs, etc. Large-city urbanites are also more likely than their small-town counterparts to have a cosmopolitan(见多识广者的) outlook, to display less responsibility to traditional kinship roles, to vote for leftist political candidates, and to be tolerant of nontraditional religious groups, unpopular political groups, and so-called undesirables. Everything considered, heterogeneity and unusual behavior seem to be outcomes of large population size.36. Which of the following statements best describes the organization of the first paragraph?A. Two contrasting views are presented.B. An argument is examined and possible solutions given.C. Research results concerning the quality of urban life are presented in order of time.D. A detailed description of the difference between urban and small-town life is given.37. According to the passage, it was once a common belief that urban residents _____.A. did not have the same interests as their neighborsB. could not develop long-standing relationshipsC. tended to be associated with bad behaviorD. usually had more friends38. One of the consequence of urban life is that impersonal relationships among neighbors _____.A. disrupt people’s natural relationsB. make them worry about crimeC. cause them not to show concern for one anotherD. cause them to be suspicious of each other39. It can be inferred from the passage that the bigger a community is, _____.A. the better its quality of lifeB. the more similar its interestsC. the more tolerant and open-minded it isD. the likelier it is to display psychological symptoms of stress40. What is the passage mainly about?A. Similarities in the interpersonal relationships between urbanites and small-town dwellers.B. Advantages of living in big cities as compared with living in small towns.C. The positive role that urbanism plays in modern life.D. The strong feeling of alienation of city inhabitants.答案36.A 37.B 38.C 39.C 40.AAbout the time that schools and others quite reasonably became interested in seeing to it that all children, whatever their background, were fairly treated, intelligence testing became unpopular.Some thought it was unfair to minority children. Through the past few decades such testing has gone out of fashion and many communities have indeed forbidden it.However, paradoxically, just recently a group of black parents filed a lawsuit(诉讼) in California claiming that the state’s ban on IQ testing discriminates against their children by denying them the opportunity to take the test. (They believed, correctly, that IQ tests are a valid method of evaluating children for special education classes.) The judge, therefore, reversed, at least partially, his original decision.And so the argument goes on and on. Does it benefit or harm children from minority groups to have their intelligence tested? We have always been on the side of permitting, even facilitating, such testing. If a child of any color or group is doing poorly in school it seems to us very important to know whether it is because he or she is of low intelligence, or whether some other factor is the cause.What school and family can do to improve poor performance is influenced by its cause. It is not discriminative to evaluate either a child’s physical condition or his intellectual level.Unfortunately, intellectual level seems to be a sensitive subject, and what the law allows us to do varies from time to time. The same fluctuation back and forth occurs in areas other than intelligence. Thirty years or so ago, for instance, white families were encouraged to adopt black children. It was considered discriminative not to do so. And then the style changed and this cross-racial adopting became generally unpopular, and social agencies felt that black children should go to black families only. It is hard to say what are the best procedures. But surely good will on the part of all of us is needed.As to intelligence, in our opinion, the more we know about any child’s intellectual level, the better for the child in question.31.Why did the intelligence test become unpopular in the past few decades?A)Its validity was challenged by many communities.B)It was considered discriminative against minority children.C)It met with strong opposition from the majority of black parents.D)It deprived the black children of their rights to a good education.32.The recent legal action taken by some black parents in California aimed to _____.A)draw public attention to IQ testingB) put an end to special educationC) remove the state’s ban on intelligence testsD) have their children enter white schools33.The author believes that intelligence testing _____.A)may ease racial confrontation in the United StatesB)can encourage black children to keep up with white childrenC)may seriously aggravate racial discrimination in the United StatesD)can help black parents make decisions about their ch ildren’s education34.The author’s opinion of child adoption seems to be that _____.A)no rules whatsoever can be prescribedB) white families should adopt black childrenC) adoption should be based on IQ test resultsD) cross-racial adoption is to be advocated35.Child adoption is mentioned in the passage to show that _____.A)good will may sometimes complicate racial problemsB)social surroundings are vital to the healthy growth of childrenC)intelligence testing also applies to non-academic areasD)American opinion can shift when it comes to sensitive issues prices答案：31.B 32.C 33.D 34.A 35.D“The world’s environment is surprisingly healthy. Discuss.” If that were an examination topic, most students would tear it ap art, offering a long list of complaints: from local smog（烟雾）to global climate change, from the felling（砍伐）of forests to the extinction of species. The list would largely be accurate, the concern legitimate. Yet the students who should be given the highest marks would actually be those who agreed with the statement. The surprise is how good things are, not how bad.After all, the world’s population has more than tripled during this century, and world output has risen hugely, so you would expect the earth itself to have been affected. Indeed, if people lived, consumed and produced things in the same way as they did in 1900 (or 1950, or indeed 1980), the world by now would be a pretty disgusting place: smelly, dirty, toxic and dangerous.But they don’t. The reasons why they don’t, and why the environment has not been ruined, have to do with prices, technological innovation, social change and government regulation in response to popular pressure. That is why today’s environmental proble ms in the poor countries ought, in principle, to be solvable.Raw materials have not run out, and show no sign of doing so. Logically, one day they must: the planet is a finite place. Yet it is also very big, and man is very ingenious. What has happened is that every time a material seems to be running short, the price has risen and, in response, people have looked for new sources of supply, tried to find ways to use less of the materials, or looked for a new substitute. For this reason prices for energy and for minerals have fallen in real terms during the century. The same is true for food. Prices fluctuate, in response to harvests, natural disasters and political instability; and when they rise, it takes some time before new sources of supply become available. But they always do, assisted by new farming and crop technology. The long-term trend has been downwards.It is where prices and markets do not operate properly that this benign（良性的）trend begins to stumble, and the genuine problems arise. Markets cannot always keep the environment healthy. If no one owns the resource concerned, no one has an interest in conserving it or fostering it: fish is the best example of this.26.According to the author, most students _____.A)believe the world’s environment is in an undesirable conditionB)agree that the environment of the world is not as bad as it is thought to beC) get high marks for their good knowledge of the world’s environmentD) appear somewhat unconcerned about the state of the world’s environment27.The huge increase in world production and population _____.A) has made the world a worse place to live inB) has had a positive influence on the environmentC) has not significantly affected the environmentD) has made the world a dangerous place to live in28.One of the reasons why the long-term trend of prices has been downwards is that _____.A)technological innovation can promote social stabilityB)political instability will cause consumption to dropC) new farming and crop technology can lead to overproductionD) new sources are always becoming available29.Fish resources are diminishing because _____.A)no new substitutes can be found in large quantitiesB)they are not owned by any particular entityC) improper methods of fishing have ruined the fishing groundsD) water pollution is extremely serious30.The primary solution to environmental problems is _____.A)to allow market forces to operate properlyB) to curb consumption of natural resourcesC) to limit the growth of the world populationD) to avoid fluctuations in prices答案：Unit 626.A 27.C 28.D 29.B 30.ARecent research has claimed that an excess of positive ions in the air can have an ill effect on people’s physical or psychol ogical health. What are positive ions? Well, the air is full of ions, electrically charged particles, and generally there is a rough balance between the positive and the negative charged. But sometimes this balance becomes disturbed and a larger proportion of positive ions are found. This happens naturally before thunderstorm, earthquakes when winds such as the Mistral, Hamsin or Sharav are blowing in certain countries. Or it can be caused by a build-up of static electricity indoors from carpets or clothing made of man-made fibres, or from TV sets, duplicators or computer display screens.When a large number of positive ions are present in the air many people experience unpleasant effects such as headaches, fatigue, irritability, and some particularly sensitive people suffer nausea or even mental disturbance. Animals are also affected, particularly before earthquakes, snakes have been observed to come out of hibernation, rats to flee from their burrows, dogs howl and cats jump about unaccountably. This has led the US Geographical Survey to fund a network of volunteers to watch animals in an effort to foresee such disasters before they hit vulnerable areas such as California.Conversely, when large numbers of negative ions are present, then people have a feeling of well-being. Natural conditions that produce these large amounts are near the sea, close to waterfalls or fountains, or in any place where water is sprayed, or forms a spray. This probably accounts for the beneficial effect of a holiday by the sea, or in the mountains with tumbling streams or waterfalls.To increase the supply of negative ions indoors, some scientists recommend the use of ionisers: small portable machines, which generate negative ions. They claim that ionisers not only clean and refresh the air but also improve the health of people sensitive to excess positive ions. Of course, there are the detractors, other scientists, who dismiss such claims and are skeptical about negative/positive ion research. Therefore people can only make up their own minds by observing the effects on themselves, or on others, of a negative rich or poor environment. After all it is debatable whether depending on seismic readings to anticipate earthquakes is more effective than watching the cat.1.What effect does exceeding positive ionization have on some people?A.They think they are insane.B.They feel rather bad-tempered and short-fussed.C.They become violently sick.D.They are too tired to do anything.2.In accordance with the passage, static electricity can be caused by___.ing home-made electrical goods.B.wearing clothes made of natural materials.C.walking on artificial floor coverings.D.copying TV programs on a computer.3.A high negative ion count is likely to be found___.A.near a pound with a water pump.B.close to a slow-flowing river.C.high in some barren mountains.D.by a rotating water sprinkler.4.What kind of machine can generate negative ions indoors?A.Ionisers.B.Air-conditioners.C.Exhaust-fansD.Vacuum pumps.5.Some scientists believe that___.A.watching animals to anticipate earthquakes is more effective than depending on seismography.B.the unusual behavior of animals cannot be trusted.C.neither watching nor using seismographs is reliable.D.earthquake答案：BCDAAThe 35 percent of African-American youth living in poverty are the most visible victims of what is often called the achievement gap. But black children of all socioeconomic levels perform worse on national tests and graduate in fewer numbers than their white middle-class peers. A 2009 study by the U.S. Department of Education’s National Center for E ducation Statistics found that African-American students scored, on average, 26 points lower than white students on their reading and math tests.Some say, as Harvard psychologist Richard J. Herrnstein and American Enterprise Institute political scientist Charles Murray did in their 1994 book, The Bell Curve, that the cause is genetic. And though The Bell Curve has been discredited in scientific circles, the idea that IQ is somehow linked to race has been slow to retreat.Others, like Cornell University re searchers Gary Evans and Michelle Schamberg, believe that “physiological stress is a plausible model for how poverty could get into the brain and eventually interfere with achievement,” as they wrote in Proceedings of the National Academy of Sciences. Our best efforts at narrowing the gap nationally — think No Child Left Behind —haven’t worked.But locally, there are now signs of hope. At the Harlem Children’s Zone’s Promise Academy charter schools, at least 97 percen t of third graders scored at or above grade level on a statewide math test in 2008, outperforming the average scores of both black and white children in New York City and New York State.What the HCZ does is first recognize that the amelioration (改善) of poverty does not begin and end with an excellent education, but also requires a full belly, parental education, safety, advocacy, and the expectation that every student will succeed. “We help pa rents and kids through the system,” HCZ founder Geoffrey Canada says. “We get them past every hindrance put in their way, whether it be at home or with social services. We can advocate on a child’s behalf, whether it be at home or in the classroom or with the juvenile justice system.” Indeed, the HCZ starts early: it provides new parents with a Baby College to teach parenting skills during the crucial first three years of a child’s life and a preschool Gems program, where kids learn not only French and Spanish but healthy eating habits to combat c hildhood obesity.The Zone also offers the HCZ Asthma Initiative to provide medical care and education to families, thus drastically cutting down on the number of school days missed by students suffering from asthma (哮´). And it has a network of afterschool programs that teach media literacy, karate (空手道), and com puter skills. It’s called the pipeline —once families enter, it’s hoped that they’ll stay until their child graduates from college. The idea is to create a safety net woven so tightly that kids can’t slip through.52. What does the author say about African-American youth as a whole?A) They have more graduates from community colleges.B) They score far below the average education level.C) They obviously are victims of the American education system.D) Their academic performances are worse than their white peers.53. According to the passage, the book The Bell Curve ________.A) has sparked a heated debate in the scientific fieldB) leads to the study on the link between race and IQC) states that intelligence has a lot to do with raceD) is against the idea that intelligence is decided by race54. Experts like Michelle Schamberg think that ________.A) the achievement gap can be narrowed easilyB) it is unreasonable to relate low achievement to povertyC) physiological stress works on achievement indirectlyD) it is impossible to achieve the goal of equal performance55. When it comes to fighting poverty, the Harlem Children’s Zone ________.A) stresses more on crime preventionB) emphasizes an all-around systemC) condemns parents as a hindranceD) sees excellent education as the sole way56. According to the passage, the purpose of HCZ’s black education is to ________.A) offer students an integrated systemB) reduce the number of asthmatic childrenC) get rid of poverty at the first placeD) set up a network to protect students from hazards参考答案：D C C B AHas your child cracked a book this summer?Although adults often jump at the chance to catch up on their reading during vacations, many children and teenagers, particularly those from low-income families, read few, if any, books during the summer break from school.But the price for keeping the books closed is a high one. Several studies have documented a “summer slide” in reading skills once school lets out each spring. The decline in reading and spelling skills are greatest among low-income students, who lose the equivalent of about two months of school each summer, according to the National Summer Learning Association, an education advocacy group. And the loss compounds each year.Now new research offers a surprisingly simple, and affordable, solution to the summer reading slide. In a three-year study, researchers at the University of Tennessee found that simply giving low-income children access to books at spring fairs — and allowing them to choose books that most interested them — had a significant effect on the summer reading gap.The study, financed by the federal Department of Education, tracked the reading habits and test scores of more than 1,300 Florida children from 17 low-income schools. At the start of the study, 852 randomly selected first- and second-graders attended a school book fair in the spring where they were allowed to browse from 600 book titles. A variety of books were offered. The children chose 12 books.The researchers al so selected at random a control group of 478 children who weren’t given reading books. Those children were offered free activity and puzzle books.The book fairs and activity book giveaways continued for three summers until the study participants reached the fourth and fifth grades. Then the researchers compared reading test scores for the two groups.Children who had received free books posted significantly higher test scores than the children who received activity books. The difference in scores was twice as high among the poorest children in the study.One of the most notable findings was that children improved their reading scores even though they typically weren’t selecting the curriculum books or classics that teachers normally assigned for summer reading. That conclusion confirms other studies suggesting that children learn best when they are allowed to select their own books.But giving children a choice in the books they read is a message many parents resist.At a bookstore recently, a study co-author, Anne McGill-Franzen, professor and director of the reading center at the University of Tennessee, said she witnessed an exchange between some mothers encouraging their fifth- and sixth-grade daughters to read biographies of historical figures, when the girls wanted to select books about Hannah Montana, a character played by the pop star Miley Cyrus.“If those books get them into reading, that has great repercussions (影响) for making them smarter,” Dr. McGill-Franzen said. “Teachers and middle-class paren ts undervalue kids’ preferences, but I think we need to give up being so uptight about children’s choices in books.”52. Several studies reveal that during summer vacations, .A) parents are eager to choose books for their children B) slide enjoys greater popularity among poor childrenC) many schools choose to close the library to save money D) children’s reading skills decline without book reading53. To solve the summer reading slide, researchers at the University of Tennessee suggest .A) schools provide free books to children B) children read in company with their parentsC) children discuss with friends after reading D) parents buy some classics for their children54. In the study, children are divided into two groups according to whether .A) they come from low-income families B) the books are offered to them for freeC) they are allowed to select their own books D) they read much and perform well in tests55. What conclusion of the study is worthy of notice according to the passage?A) Children tend not to read the curriculum books in summer. B) Poor students get the lowest scores in the reading test.C) Children given choice in books improve their reading. D) Teachers’ summer reading assignment fails to work on children.56. What does Anne McGill-Franzen’s experience in the bookstore illustrate?A) Parents oppose giving children a choice in books. B) Reading about fictional figures makes children smarter.C) Many children books are undervalued in bookstores. D) There exists generation gap in selecting reading material.参考答案：D A C C A1,According to BT's futurologist, Ian Pearson, these are among the developments scheduled for the first few decades of the new millennium(a period of 1，000 years), when supercomputers will dramatically accelerate progress in all areas of life.Pearson has __1__ together to work of hundreds of researchers around the world to produce a __2__ millennium technology calendar that gives the latest dates when we can expect hundreds of key __3__ and discoveries to take place. Some of the biggest developments will be in medicine, including an __4__ life expectancy and dozens of artificial organs __5__ into use between now and 2040.Pearson also __6__ a breakthrough in computer human links. "By linking __7__ to our nervous system, computers could pick up __8__ we feel and, hopefully, simulate __9__ too so that we can start to __10__ full sensory environments, rather like the holidays in Total Recall or the Star Trek holodeck," he says.But that, Pearson points __11__, is only the start of man-machine __12__:"It will be the beginning of the long process of integration that will __13__ lead to a fully electronic human before the end of the next century."__14__ his research, Pearson is able to put dates to most of the breakthroughs that can be predicted. However, there are still no __15__ for when faster-than-light travel will be __16__, or when human cloning will be perfected, or when time travel will be possible.But he does __17__ social problems as a result of technological advances. A boom in neighborhood surveillance cameras will, for example, __18__ problems in 2010, while the arrival of synthetic __19__ robots will mean people。