阅读理解Directions: In this part for the test, there will be 5 passages for you to read. Each passage is followed by 4 questions or unfinished statement, and each question or unfinished statement is followed by four choices marked A, B, C and D. You are to decide on the best choice by blackening the corresponding letter on the ANSWER SHEET.Passage Two Researchers have created male mice with no trace of a Y chromosome, supposedly the defining hallmark of being male.Reproductive biologist Monika Ward of University of Hawaii in Honolulu and colleagues started with mice that have only one X chromosome ( and no second sex chromosome). Normally those animals would develop as females. But when the researchers manipulated genes found on the X and another chromosome, the mice became males that could produce immature sperm. Those engineered males fathered offspring with reproductive assistance from the researchers, who injected the immature sperm into eggs, Ward and colleagues report in the Jan. 29 Science.The experiments demonstrate that there are multiple ways to make males, says Richard Behringer, a developmental geneticist at MD Anderson Cancer Center in Houston. “They’ve done it without any Y chromosome gene information,” he says “There’s not even a sniff of the Y around. ”At first glance, the experiments would seem to suggest Y chromosomes aren’t necessary for reproduction, which hints that evolution may eventually show Y’s the door. “To me it is a paradigm of the decline and fall of the Y chromosome，” says reproductive biologist Jennifer Marshall Graves of La Trobe University in Melbourne, Australia.But Ward and other researchers say the Y isn’t going anywhere and that interpreting the new results as the chromosome’s death knell is wrong. Because the Y-less males needed help to reproduce, “clearly we need the Y chromosome for full natural male reproduction，” says Mary Ann Handel, a reproductive biologist at the Jackson Laboratory in Bar Harbor, Maine.Ward and colleagues had previously shown that two chromosome genes一Sry and Eif2 s3y—are crucial for male mouse development. Sry is a master gene that turns on male developmental programming in early embryos. It turns on a gene called Sox9, which then sets off a biochemical chain reaction that leads to male development.But in the new experiments, the researchers turned on Sox9 through other means. Activating Sox9 in a genetically female embryo will cause it to develop as a male, Ward and colleagues found. But those males didn’t make sperm. “The testes were empty,” says Ward.In order to produce sperm, mice need the Eif2s3y gene, the researchers had previously discovered. In the new experiment, the mice were missing the gene because they didn’t have Y chromosomes. So researchers substituted a similar gene from the X chromosome called Eif2s3x. Only one copy of the Y version is needed to make immature, tailless sperm, but it takes at least five copies of the X version to do the same thing. “ This indicates that the Y chromosome gene is the strong one,，’ says Ward.Her research suggests that the Y chromosome has optimized production from genes that are necessary for making males. Making just the right dose of male development factors is how the Y protects itself from evolutionary erasure, Ward says. “ Our work does not support that the Y chromosome will disappear. ’，Graves disagrees, Ward’s work is “a lovely example of how you can lose even a really important gene,” she says. At least two species of rodents have already jettisoned their Y chromosomes entirely. Primates, including humans, don’t have EiJSs3y genes on their Y chromosomes. The new work may help explain how primates get along without the gene, Graves suggests, and the research may “give us useful information about what happens at the end of the Y chromosome. ”

阅读理解The Benefits of New Urbanism(1) New urbanism is the most important planning movement in this century, and is about creating a better future for us all. It is an international movement to reform the design of the built environment, and is about raising our quality of life and standard of living by creating better places to live in. New urbanism is the revival of our lost art of place-making, and is essentially a re-ordering of the built environment into the form of complete cities, towns, villages, and neighborhoods—the way communities have been built for centuries around the world. New urbanism involves fixing and infilling cities, as well as the creation of compact new towns and villages. The benefits of new urbanism are as follows:Benefits to Residents(2) Higher quality of life; better places in which to live, work, and play; more stable property values; less traffic congestion and less driving; healthier lifestyle with more walking and less stress; close proximity to main street retail and services; close proximity to bike trail, parks, and nature; pedestrian friendly communities offer more opportunities to get to know others in the neighborhood and town, resulting in meaningful relationships with more people, and friendlier town; more freedom and independence to children, the elderly, and the poor in being able to get to jobs recreation, and services without the need for a car or someone to drive them; great savings to residents and school boards in reduced busing costs from children being able to walk or bicycle to neighborhood schools; more diversity and smaller, unique shops and services with local owners who are involved in community; big savings by driving less, and owning less cars; less ugly, congested sprawl to deal with daily; better sense of place and community identity with more unique architecture; more open space to enjoy that will remain open space; more efficient use of tax money with less spent on utilities and roads used for the sprawl.Benefits to Businesses(3) Increased sales due to more foot traffic and people spending less on cars and gas; more profits due to spending less on advertising and large signs; better lifestyle by living near work units saves the stressful and costly commute; economies of scale in marketing due to close proximity and cooperation with other local business incubation; lower rents due to smaller spaces and smaller parking lots; healthier lifestyle due to more walking and being near healthier restaurants; more community involvement from being part of community and knowing residents.(4) Benefits to Developers. More income potential from higher density mixed-use projects due to more leasable square footage, more sales per square foot, and higher property values and selling prices; faster approvals in communities that have adopted smart growth principles resulting in cost/time sayings: cost savings in parking facilities in mixed-use properties due to sharing of spaces throughout the day and night, resulting in less duplication in providing parking; less need for parking facilities due to mix of residences and commercial uses within walking distance of each other; less impact on roads/traffic, which can result in lower impact fees; lower cost of utilities due to compact nature of new urbanist design; faster sellout due to greater acceptance by consumers from a wider product range resulting in wider market share.Benefits to Municipalities(5) Stable, appreciating tax base; less spent per capita on infrastructure and utilities than typical suburban development due to compact high-density nature of projects; increased tax base due to more buildings packed into a tighter area; less traffic congestion due to walkability of design; less crime and less money spent on police due to the presence of more people day and night; better overall community image and sense of place; less incentive to sprawl when urban core area is desirable; easy to install transit where it’s not, and improve it where it is; greater civic involvement of population leading to better governance.(6) The most effective way to implement new urbanism it to plan for it, and write it into zoning and development codes. This directs all future development into this form.(7) Increasingly, regional planning techniques are being used to control and shape growth into compact, high-density, mixed-use neighborhoods, villages, towns, and cities. Planning new train systems (instead of more roads) delivers the best results when designed in harmony with regional land planning known as Transit Oriented Development (TOD). At the same time, the revitalization of urban areas directs and encourages infill development back into city centers.(8) Planning for compact growth, rather than letting it sprawl out, has the potential to greatly increase the quality of the environment. It also prevents congestion problems and the environmental degradation normally associated with growth.(9) There are some obstacles in implementation of new urbanism. The most important obstacle to overcome is the restrictive and incorrect zoning codes currently in force in most municipalities. Current codes do not allow new urbanism to be built, but do allow sprawl.(10) An equally important obstacle is the continuous road building and expansion taking place in every community across America. This encourages more driving and more sprawl which has a domino effect on increasing traffic congestion across the region. Halting road projects and building new train system can help reverse this problematic trend.

阅读理解The word science is heard so often in modern times that almost everybody has some notion of its meaning. The meaning of the term is confusing, but everyone should understand its meaning and objectives. Just to make the explanation as simple as possible, suppose science is defined as classified knowledge.Even in true sciences, distinguishing fact from fiction is not always easy. For this reason great care should be taken to distinguish between beliefs and truths. For example, hypotheses and theories are attempts to explain natural phenomena. From these positions scientists continue to experiment and observe until they are proved. The exact status of any explanation should be clearly labeled to avoid confusion.The objectives of science are primarily the discovery and the subsequent understanding of the unknown. Man cannot be satisfied with recognizing that secrets exist in nature or that questions are unanswerable; he must solve them. Toward that end, specialists in the field of biology and related fields of interest are directing much of their time and energy.Actually, two basic approaches lead to the discovery of new information. One, aimed at satisfying curiosity, is referred to as pure science. The other is aimed at using knowledge for specific purposes such as improving health, or creating new consumer products. In this case knowledge is put to economic use. Such an approach is referred to as applied science.Sometimes practical-minded people miss the point of pure science in thinking only of its immediate application for economic reward. Chemists responsible for discoveries could hardly anticipated that their findings would one day result in applications of such a practical nature as those directly related to life and death. The discovery of one bit of information opens the door to the discovery of another. However, one should remember that the construction of the microscope had to precede the discovery of the cell. Many scientists dedicating their lives to purer science are not apologetic about ignoring the practical side of their discoveries; they know from experience that most knowledge is eventually applied.

阅读理解Passage Two: Questions are based on the following passage

阅读理解Passage Three: Questions are based on the following passage

阅读理解Passage Two: Questions are based on the following passage

阅读理解Passage One: Questions are based on the following passage

阅读理解Passage three: Questions are based on the following passage

阅读理解In 1784, five years before he became president of the United States, George Washington, 52, wasnearly toothless. So he hired a dentist to transplant nine teeth into his jaw, having extracted themfrom the mouths of his slaves.That’s a far different image from the cherry-tree-chopping George most people remember from theirhistory books. But recently, many historians have begun to focus on the roles slavery played in thelives of the founding generation. They have been spurred in part by DNA evidence made available in1998, which almost certainly proved Thomas Jefferson had fathered at least one child with his slaveSally Hemings. And only over the past 30 years have scholars examined history from the bottom up.Works of several historians reveal the moral compromises made by the nation’s early leaders and thefragile nature of the country’s infancy. More significantly, they argue that many of the FoundingFathers knew slavery was wrong — and yet most did little to fight it.More than anything, the historians say, the founders were hampered by the culture of their time.While Washington and Jefferson privately expressed distaste for slavery, they also understood that itwas part of the political and economic bedrock of the country they helped to create.For one thing, the South could not afford to part with its slaves. Owning slaves was “like having alarge bank account,” says Wiencek, author of An Imperfect God: George Washington, His Slaves,and the Creation of America. The southern states would not have signed the Constitution withoutprotections for the “peculiar institution,” including a clause that counted a slave as three fifths of aman for purposes of congressional representation. And the statesmen’s political lives depended onslavery. The three-fifths formula handed Jefferson his narrow victory in the presidential election of1800 by inflating the votes of the southern states in the Electoral College. Once in office, Jeffersonextended slavery with the Louisiana Purchase in 1803; the new land was carved into 13 states,including three slave states.Still, Jefferson freed Hemings’s children, though not Hemings herself or his approximately 150 otherslaves. Washington, who had begun to believe that all men were created equal after observing thebravery of the black soldiers during the Revolutionary War, overcame the strong opposition of hisrelatives to grant his slaves their freedom in his will. Only a decade earlier, such an act would haverequired legislative approval in Virginia.

阅读理解The old belief that the universe never changes is quite wrong. Even before the invention of the telescope, astronomers noticed that bright stars suddenly appear in the sky, and then later disappear.【B1】______In fact we now know that they are really old stars which are slowly dying. A recent case of a nova occurred in 1918, and one of the few people who saw this was the American astronomer Edward Barnard. He was driving along in a car, occasionally looking up into the sky. Suddenly he noticed a star that he had never seen before, and exclaimed, “That star should not be there!”He was in fact watching the explosion of a nova. 【B2】______As they do so, they let out huge clouds of material. Sometimes as large as the earth, and these explode into space at a speed of about 8, 000, 000 kilometers per hour. When this happens, the hotter parts of the star become visible, and this is why novae are so bright. Although the explosions are huge on a human scale, they only consume a small part of the dying star’s energy. 【B3】______Indeed, there are even some stars which explode once a fortnight. There are other old stars which do not die slowly, but are completely destroyed by one great explosion.【B4】______The explosion of a supernova is equivalent to about a million, million, million, million hydrogen bombs going off at the same time. Just before the explosion the star’s density become very great and it spins at a very high speed. A matchbox of material taken from the star at that time would weigh about 1,000 tons, and the star would be turning at about 16,000,000 kilometers per hour.【B5】______One supernova which Chinese astronomers observed in 1054 can still be seen by us today. It has been shining for at least nine hundred years. A. Novae are old stars which are slowly dying. B. They are known as “supernovae.”C. The death is a slow one, and the star may continue to explode for thousands of years. D. The explosion of a supernova is like a cosmic bomb. E. The explosion itself occurs suddenly, in the space of a minute, but the supernova continues to shine long after the event. F. These stars were called “novae”because they were thought to be new.

阅读理解Passage Two Skilled clinical history-taking and physical examination remain essential as the basis of the disease diagnosis and management, aided by investigations such as radiological or biochemical tests

阅读理解When you think of the tremendous technological progress we have made, it’s amazing how little wehave developed in other respects. We may speak contemptuously of the poor old Romans becausethey relished the orgies of slaughter that went on in their arenas. We may despise them because theymistook these goings on for entertainment. We may forgive them condescendingly because theylived 2000 years ago and obviously knew no better. But are our feelings of superiority really justified?Are we any less blood-thirsty? Why do boxing matches, for instance, attract such universal interest?Don’t the spectators who attend them hope they will see some violence? Human beings remains asbloodthirsty as ever they were. The only difference between ourselves and the Romans is that whilethey were honest enough to admit that they enjoyed watching hungry lions tearing people apart andeating them alive, we find all sorts of sophisticated arguments to defend sports which should havebeen banned long age; sports which are quite as barbarous as, say, public hangings or bearbaiting.It really is incredible that in this day and age we should still allow hunting or bull-fighting, that weshould be prepared to sit back and watch two men batter each other to pulp in a boxing ring, that weshould be relatively unmoved by the sight of one or a number of racing cars crashing and burstinginto flames. Let us not deceive ourselves. Any talk of ‘the sporting spirit’ is sheer hypocrisy. Peopletake part in violent sports because of the high rewards they bring. Spectators are willing to pay vastsums of money to see violence. A world heavyweight championship match, for instance, is frontpage news. Millions of people are disappointed if a big fight is over in two rounds instead of fifteen.They feel disappointment because they have been deprived of the exquisite pleasure of witnessingprolonged torture and violence.Why should we ban violent spoils if people enjoy them so much? You may welt ask. The answer issimple: they arc uncivilized. For centuries man has been trying to improve himself spiritually andemotionally — admittedly with little success. But at least we no longer tolerate the sight madmencooped up in cages, or public floggings of any of the countless other barbaric practices which werecommon in the past. Prisons are no longer the grim forbidding places they used to be. Social welfaresystems are in operation in many parts of the world. Big efforts are being made to distribute wealthfairly. These changes have come about not because human beings have suddenly and unaccountablyimproved, but because positive steps were taken to change the law. The taw is the biggest instrumentof social change that we have and it may exert great civilizing influence. If we banned dangerous andviolent sports, we would be moving one step further to improving mankind. We would recognize thatviolence is degrading and unworthy of human beings.

阅读理解As you all know, the United States is a country on wheels. Nearly eight million new cars are made each year; four households out of five own at least one car, and more than a quarter have two each. Yet you’ll be surprised to learn that some of the car-owners even suffer from malnutrition.In 1968, a nation-wide survey of malnutrition was made for the first time. It found that 10 million people are suffering in health through inadequate feeding; the causes of their plight were varied. Unemployment over a long period should be considered as the main factor. And unemployment, strange to say, nine times out of ten results from automation, both in industrial and agricultural areas. For example, in the rural South when a cotton plantation suddenly cuts its force from 100 people to three, the problem to help the displaced arises. So is the case with industrial automation. In fact, probably 2 million jobs are made unnecessary each year in the whole country as a result of the automation process, thus making unemployment a chief social concern. According to government statistics, the number of people unemployed was over 5 percent for the period from 1958 to 1963. In July 1981, it rose to 7.8 percent. As a matter of fact, it has long been known that even during the most prosperous periods there have been people without enough to eat. So I think that’s why President Kennedy said in his inauguration speech in 1961, if the government did not help the poor, it could not save the rich.In 1966, the Social Security Administration calculated that a family of four needed an income of $3,355 a year to be above the line of poverty. And in 1977, the average poverty line of the country was slightly more than $6,200 annual income for a non-farm family of four. According to the Social Security Act, families of that size below poverty line are eligible to receive benefits from the special welfare program. The average weekly payment of benefits now is equivalent to 36 percent of the worker’s normal wage. And the number of people who receive government benefits is increasing. In 1973, social insurance payments by governments, mainly to old age pensioners and people who had lost their jobs or were off work through illness, amounted to $86,000 million. Those not fully qualified for insurance payments received $29,000 million in public aid.But problems still exist. Many people are not reached by the anti-poverty program, because local authorities and agencies do not want to play their part or do not gave the resources to do so. Some poor people will not accept help for various reasons. Of course, there are some more important factors which lie in the structure of the society, but I don’t consider it necessary to dig into them here. Yet we will perhaps agree that social welfare programs have solved to some extent the problems of feeding, clothing and housing those below the poverty line. On the whole, it perhaps might be said that American people are living a better life than people in most other countries.

阅读理解 Despite the numerous warnings about extreme weather, rising sea levels and mass extinctions, one message seems to have got lost in the debate about the impact of climate change. A warmer world won't just be inconvenient. Huge swathes (片) of it, including most of Europe, the US and Australia as well as all of Africa and China will actually be uninhabitable—too hot, dry or stormy to sustain a human population. This is no mirage. It could materialize if the world warms by an average of just 4℃, which some models predict could happen as soon as 2050. This is the world our children and grandchildren are going to have to live in. So what are we going to do about it? One option is to start planning to move the at-risk human population to parts of the world where it will still be cool and wet. It might seem like a drastic move, but this thought experiment is not about scaremongering (危言耸听). Every scenario is extrapolated from predictions of the latest climate models, and some say that 4℃ may actually turn out to be a conservative estimate. Clearly this glacier-free, desertified world—with its human population packed into high-rise cities closer to the poles—would be a last resort. Aside from anything else, it is far from being the most practical option: any attempt at mass migration is likely to fuel wars, political power struggles and infighting. So what are the alternatives? The most obvious answer is to radically reduce carbon dioxide levels now, by fast-tracking green technologies and urgently implementing energy-efficient measures. But the changes aren't coming nearly quickly enough and global emissions are still rising. As a result, many scientists are now turning to 'Earth's plan B'. Plan B involves making sure we have large scale geoengineering technologies ready and waiting to either suck CO2 out of the atmosphere or deflect the sun's heat. Most climate scientists were once firmly against fiddling with the Earth's thermostat, fearing that it may make a bad situation even worse, or provide politicians with an excuse to sit on their hands and do nothing. Now they reluctantly acknowledge the sad truth that we haven't managed to reorder the world fast enough to reduce CO2 emissions and that perhaps, given enough funding research and political muscle, we can indeed design, test and regulate geoengineering projects in time to avert the more horrifying consequences of climate change. Whatever we do, now is the time to act. The alternative is to plan for a hothouse world that none of us would recognize as home.

阅读理解Passage Two: Questions are based on the following passage

阅读理解Passage four: Questions are based on the following passage

阅读理解How does the author feel about the prospect of protecting endangered species from being extinct?

阅读理解Passage one: Questions are based on the following passage

阅读理解Passage Five Is the profession of medicine in retreat? Im reminded of this with September welcoming a new influx（流入）of medical students

阅读理解 Stephanie Smith, a children's dance instructor, thought she had a stomach virus. The aches and cramping were tolerable that first day, and she finished her classes. Then her diarrhea turned bloody. Her kidneys shut down. Seizures knocked her unconscious. The convulsions grew so relentless that doctors had to put her in a coma for nine weeks. When she emerged, she could no longer walk. The affliction had ravaged her nervous system and left her paralyzed from the waist down. Ms. Smith, 22, was found to have a severe form of food-borne illness caused by E. coli, which Minnesota officials traced to the hamburger that her mother had grilled for their Sunday family party. In the simplest terms, she ran out of luck in a food-safety game of chance whose rules and risks are not widely known. Meat companies and grocers have been barred from selling ground beef tainted by the virulent strain of E. coli known as o157:H7 since 1994. Yet tens of thousands of people are still sickened annually by this pathogen with hamburger being the biggest culprit. Ground beef has been blamed for 16 outbreaks in the last three years alone. This summer, contamination led to the recall of beef from nearly 3,000 grocers in 41 states. Ms. Smith's reaction to the virulent strain of E. coli was extreme, but tracing the story of her burger shows that neither the system meant to make the meat safe, nor the meat itself, is what consumer have been led to believe. Ground beef is usually not simply a chunk of meat run through a grinder. Instead, a single portion of hamburger meat is often an amalgam of various grades of meat from different parts of cows and even from different slaughterhouses. This makes the costs 25% less than it would have for cuts of whole meat. These cuts of meat are particularly vulnerable to E. coli contamination, food experts and officials say. Despite this, there is no federal requirement for grinders to test their ingredients for the pathogen. Those ingredients include cuts from areas of the cow that are more likely to have had contact with feces, which carries E. coli, industry research shows. Yet most meat companies rely on their suppliers to check for the bacteria and do their own testing only after the ingredients are ground together. Unwritten agreements between some companies appear to stand in the way of ingredient testing. Many big slaughterhouses will sell only to grinders who agree not to test their shipments for E. coli for fear of a recall of ingredients they sold to others. 'Ground beef is not a completely safe product,' said Dr. Jeffrey Bender, a food safety expert at the University of Minnesota who helped develop systems for tracing E. coli contamination. He said that while outbreaks had been on the decline, 'unfortunately it looks like we are going a bit in the opposite direction.'