单选题The government regulate private enterprises for the main purpose of______ .

单选题 Questions 17 to 20 are based on the following talk about school meals in the UK. You now have 20 seconds to read Questions 17 to 20.

单选题When Liam McGee departed as president of Bank of America in August, his explanation was surprisingly straight up. Rather than cloaking his exit in the usual vague excuses, he came right out and said he was leaving "to pursue my goal of running a company". Broadcasting his ambition was "very much my decision", McGee says. Within two weeks, he was talking for the first time with the board of Hartford Financial Services Group, which named him CEO and chairman on September 29. McGee says leaving without a position lined up gave him time to reflect on what kind of company he wanted to run. It also sent a clear message to the outside world about his aspirations. And McGee isn't alone. In recent weeks the No. 2 executives at Avon and American Express quit with the explanation that they were looking for a CEO post. As boards scrutinize succession plans in response to shareholder pressure, executives who don't get the nod also may wish to move on. A turbulent business environment also has senior managers cautious of letting vague pronouncements cloud their reputations. As the first signs of recovery begin to take hold, deputy chiefs may be more willing to make the jump without a net. In the third quarter, CEO turnover was down 23% from a year ago as nervous boards stuck with the leaders they had, according to Liberum Research. As the economy picks up, opportunities will abound for aspiring leaders. The decision to quit a senior position to look for a better one is unconventional. For years executives and headhunters have adhered to the rule that the most attractive CEO candidates are the ones who must be poached. Says Korn/Ferry senior partner Dennis Carey: "I can't think of a single search I've done where a board has not instructed me to look at sitting CEOs first. " Those who jumped without a job haven't always landed in top positions quickly. Ellen Marram quit as chief of Tropicana a decade age, saying she wanted to be a CEO. It was a year before she became head of a tiny Internet-based commodities exchange. Robert Willumstad left Citigroup in 2005 with ambitions to be a CEO. He finally took that post at a major financial institution three years later. Many recruiters say the old disgrace is fading for top performers. The financial crisis has made it more acceptable to be between jobs or to leave a bad one. "The traditional rule was it's safer to stay where you are, but that's been fundamentally inverted," says one headhunter. "The people who've been hurt the worst are those who've stayed too long. /

单选题 Ever since Gregor Mendel' s famous experiments with hybrid sweet peas, it has been known that there must be unitary elements within the cells which exert control over inherited characteristics, and for a long time there was considerable speculation about what these were. These elements came to be known as genes, and although they were long treated as hypothetical constructs, a great deal of knowledge about them slowly accumulated. It came to be known, for example, that each gene had to be passed along virtually unchanged from generation to generation; that there must be many thousands of these particles in every human cell, distributed unevenly among the twenty-three pairs of chromosomes; that each gene must occupy a very definite place (locus) on its chromosome; and that each pair of homologous chromosomes had to contain homologous assortments of genes, arranged with few exceptions in precisely the same order on each member of the chromosome pail' s. A wonderfully complex and fruitful system thus emerged about an aspect of the world which no one has ever directly observed. Let us now briefly turn to some of the newly acquired insights which have greatly expanded the already impressive theory of genetics. Genes are, of course, too small to be seen even by the most powerful electron microscopes, but recent research by geneticists, microbiologists, and biochemists has rapidly advanced our information about their constitution and action. The chemical substance of which the genes and thus the chromosomes are made, is now known to be deoxyribonucleic acid (DNA), a giant molecule containing a double-spiral strand of material which embodies the genetic code. The chromosomes consist of long strands of DNA, which, although it is capable of transmitting vastly complex "code messages", is comprised of combinations of only four primary chemical subunits, or "code letters". This great insight into the structure and functioning of genetic material, which was first proposed by James D. Watson and Francis H. C. Crick in 1953, involves a new description of what genes are like. A gene is simply a specific portion of the double-spiral strand of DNA which consists of a particular combination of the code letters that spell out a particular code word. Various combinations of the four code letters, forming different code words, provide the biochemical information used in the construction of the different proteins in the cell. Many of these proteins act as enzymes. The enzymes, as has been pointed out above, are the biological catalysts which direct all the chemical or metabolic reactions that are going on continuously in all cells. These metabolic functions are, of course, the basis of all the physical growth and development of any living organism. The code is embodied in the DNA of the chromosomes and genes, but exactly how does this code deter mine the production of proteins. Obviously, the code must be transmitted to the sites at which the actual work of protein synthesis is carried out. The material which accomplishes this task is ribonucleic acid (RNA, a substance very similar to DNA and complementary to it. From the code site on the linear DNA molecule, which is the gene), RNA, the messenger, carries the code to the cellular particles out into the cytoplasm of the cell, where proteins are manufactured. This messenger RNA provides the pattern, and another type of RNA, transfer RNA, collects from within the cytoplasm the raw materials, the amino acids, from which the proteins are made. With the pattern and the materials, the proteins are formed, one step at a time. These proteins act as enzymes or biological catalysis. They exist in all living organisms and control their growth and function through the control of the chemical transformations involved in metabolism. A very large number of enzymes are present in any living creature, and the absence or malformation of any enzyme can destroy the normal sequence of metabolism of a given biochemical substance. We can thus see that genetic activity takes the form of biochemical regulation, the genes determining the formation of enzymes. In this sense, all genetic disorders are primarily metabolic defects (Garrod, 1908). A defective or changed gene will in turn produce a change in the protein with which it is associated. The only result of such a change may be a slight alteration in the function of the protein, and there may thus be little or no observable effect. If the change or defect takes place within the code message for an essential element of the protein, however, the enzyme activity of this protein may be rendered completely inactive. If this happens, the result can be grave trouble: perhaps death, serious disease, or severe mental retardation due to poisoning of the central nervous system by a metabolite that is toxic to this system. The error in enzyme synthesis may begin to be important, so that the structure of the central nervous system is faulty almost from the beginning of embryonic life, or it may become important much later in the life cycle. It is quite likely that, in the foreseeable future, many essential biochemical processes will be understood in terms of the precise genetic codes responsible for them. All of the amino acids have already yielded to such analysis; their codes have been identified. With understanding may come control and prevention, such as may be possible by administration of the lacking enzymes, dietary control of substances which the individual is unable to metabolize, or transplantation of normal tissue to the diseased individual to correct the metabolic error.

单选题 Questions 14 to 16 are based on a report that weather delay US shuttle launch. You now have 15 seconds to read Questions 14 to 16.

单选题Research carried out in the recent opinion polls shows that

单选题Most of us are taught to pay attention to what is said—the words. Words do provide us with some information, but meanings are derived from so many other sources that it would hinder our effectiveness as a partner to a relationship to rely too heavily on words alone. Words are used to describe only a small part of the many ideas we associate with any given message. Sometimes we can gain insight into some of those associations if we listen for more than words. We don't always say what we mean or mean what we say. Sometimes our words don't mean anything except "I'm letting off some steam. I don't really want you to pay close attention to what I'm saying. Just pay attention to what I'm feeling". Mostly we mean several things at once. A person wanting to purchase a house says to the current owner, "This step has to be fixed before I'll buy. " The owner says, "It's been like that for years. " Actually, the step hasn't been like that for years, but the unspoken message is. "I don't want to fix it. We put up with it. Why can't you?" The search for a more expansive view of meaning can be developed of examining a message in terms of who said it, when it occurred, the related conditions or situations, and how it was said. When a message occurs can also reveal associated meaning. Let us assume two couples do exactly the same amount of kissing and arguing. But one couple always kisses after an argument and the other couple always argues after a kiss. The ordering of the behaviors may mean a great deal more than the frequency of the behavior. A friend's unusually docile behavior may only be understood by noting that it was preceded by situations that required an abnormal amount of assertiveness. Some responses may be directly linked to a developing pattern of responses and defy logic. For example, a person who says "No!" to a serials of charges like "You're dumb," "You're lazy," and "You're dishonest," may also say "No!" and try to justify his or her response if the next statement is "And you're good looking. " We would do well to listen for how messages are presented. The words, "It sure has been nice to have you over," can be said with emphasis and excitement or ritualistically. The phrase can be said once or repeated several times. And the meanings we associate with the phrase will change accordingly. Sometimes if we say something infrequently, it assumes more importance; sometimes, the more we say something, the less importance it assumes.

单选题Novel approaches to baby making seem to be coming at us so fast that we hardly have time to digest one before the next one hits — test-tube babies, egg donation, surrogacy, cloning and now sex selection. And just as with earlier methods, the new sperm-separation technique announced last week has triggered plenty of ethical concern. Only a few critics have argued that tampering with nature to avoid a sex-linked genetic disease should be taboo. But plenty have expressed misgivings about using the new technology more casually, to balance families, or simply because parents prefer boys or girls. Such choices, critics say, could lead to an imbalance in the sex ratio, with drastic consequences for society. These arguments are not very persuasive. In some developing countries where boys are more highly valued than girls, sex selection is already standard practice, accomplished by means of infanticide of amniocentesis and abortion. The new sperm-separation technique makes it easier for more people to practice sex selection in these countries. This could skew the already tilting sex ratio even further in favor of boys. In the short term, such demographic shifts could cause enormous societal problems as men, for example, find it increasingly difficult to find women to marry. In the long term, however, both evolutionary and economic theories tell us that as girls become scarcer, they will become more highly valued, perhaps to the point at which more people will select for girls than against them. In America and other Western countries there seems to be little chance of the sexes going far out of balance at all. Polls show that a majority of Americans view a perfect family as having one boy and one girl. If everyone used sex selection to achieve perfection, the result would be perfect balance. Of course, some prospective parents do prefer children of one sex or the other. But such preferences would presumably balance out as well. Regarding the argument that choosing gender goes against nature: the same objection was used in earlier times by people horrified by vaccines or heart transplants, which are now completely acceptable. Every time we use medicine to cure a disease or prevent a death, we go against nature willingly. Admittedly, sex selection for family balancing cures no disease. In fact, though, no form of baby making solves a medical problem. Sex selection, moreover, is medically benign in comparison with most reproductive technologies. No surgery is involved, and the entire process can theoretically be performed without a physician. Children born through this process can't distinguish from other children. For these reasons, I suspect that as sex selection and other reproductive technologies become more efficient and less costly, they may be embraced by American families of even modest means who ask themselves, why not? What was once unimaginable could become routine and the link between the sex act and reproduction will no longer be seen as sacred. Ultimately, this may prove to be the real significance of sex selection: by breaching a powerful psychological barrier, it will pave the way for true designer babies, who could really turn society upside down.

单选题 Questions 14 to 16 are based on the following conversation on a taxi ride between the driver (the man) and a passenger (the woman). You now have 15 seconds to read Questions 14 to 16.

单选题It can be inferred from the last paragraph that

单选题Questions 17—20 are based on the following talk about the language ability.

单选题{{B}}TEXT 3{{/B}} Dozens of companies these days are hawking genetic testing kits, which claim to give consumers a glimpse of their future health. But how accurate are they? Perhaps not very, according to witnesses at U. S. Senate hearing here today, as well a report released concurrently by the Government Accountability Office (GAO), Congress's investigation arm. There are genetic tests for more than 1000 conditions. While in some cases, such as cystic fibrosis, having a particular set of mutations all but guarantees disease, in many others it correlates only with an increase in disease risk. For example, mutations in the BRCA1 and BRCA2 genes correspond with a roughly 50% to 80% risk of breast cancer. DNA tests are regulated by the Clinical Laboratory Improvement Amendments (CLIA), which, some critics have charged, lacks the ability to effectively oversee complex and rapidly changing diagnostics. While most DNA tests are administered in a doctor's office, some can be ordered from companies online. A subset of these tests, called "nutragenic" DNA tests, claim to provide consumers with information about diseases for which they're supposedly at risk as well as, in some cases, dietary advice, such as pills sold by the company, that may counter the hazard. It's this class of tests that GAO and the Senate's Special Committee on Aging tackled. To conduct the investigation, the GAO team ordered DNA tests online, all of which examined between four and 19 genes, from four companies: Market America, Genelex, Sciona, and Suracell. Using DNA samples from a 48-year-old man and the 9-month-old daughter of GAO's Gregory Kutz, who helped assemble the report, the team created 14 fictitious characters with various lifestyles. If the companies were truly focusing on genetics, many of the results that came back didn't make sense. In some cases, two DNA samples from the same source came back with a different list of disease risks. In addition, the companies recommended nutritional formulas tailored to an individual's DNA, but the investigators found that identical formulas were prescribed for people with different DNA. The DNA tests "threaten more than the public's pocketbook; they threaten public health," Kathy Hudson of the Genetics and Public Policy Center testified at the hearing. Hudson told the senators that legislation was needed to better regulate and validate these tests. Representatives from the companies, however, took a different view. Rosalynn Gill-Garrison, the chief science officer of Sciona, based in Boulder, Colorado, emphasized that her firm's products were safe, effective, and ethically appropriate.

单选题 {{B}} Questions 14～16 are based on the fallowing talk. You now have 15 seconds to read Questions 14～16.{{/B}}

单选题 {{I}}Questions 11 - 13 are based on the following talk. You now have 15 seconds to read Questions 11 - 13.{{/I}}

单选题Painting your house is like adding something to a huge communal picture in which the rest of the painting is done either by nature or by other people. The picture is not static; it changes as we move about, with the time of day, with the seasons, with new planting, new buildings and with alterations to old ones. Any individual house is just a fragment of this picture, nevertheless it has the power to make or mark the overall scene. In the past people used their creative talents in painting their homes, with great imagination and in varied but always subtly blending colors. The last vestiges of this great tradition can still be seen in the towns of the extreme west of Ireland. It has never been recognized as an art form, partly because of the physical difficulty of hanging a street in a gallery and partly because it is always changing, as paint fades and is renewed. Also it is a communal art which cannot be identified with any person, except in those many cases where great artists of the past found inspiration in ordinary street scenes and recorded them in paint. Following the principles of decoration that were so successful in the past, you should first take a long look at the house and its surroundings and consider possible limitations. The first concerns the amount of color and intensity in the daylight in Britain. Colors that look perfectly in keeping with the sunny, clear skies of the Mediterranean would look too harsh in the grayer light of the north. Since bright light is uncomfortable for the eyes, colors must be strong in order to be seen clearly. Viewed in a dimmer light they appear too bright. It is easy to see this if you look at a brick house while the sun is alternately shining and then going behind a cloud. The brick work colors look much more intense when the sun is hidden. The second limitation is the colors of the surroundings: the colors which go best with Cotswold stone and a rolling green countryside will be different from those that look best by the sea or in a red--brick/ blue--slate industrial town. In every area there are always colors that at once look in keeping. In many areas there are distinctive traditions in the use of color that may be a useful guide. The eastern countries of England and Scotland, particularly those with a local tradition of rendering of plastering, use colors applied solidly over the wall. Usually only the window frames and doors are picked out in another color, often white or pale grey. Typical wall colors are the pink associated with Suffolk and pate buffs. Much stronger colors such as deep earth red, orange, blue and green are also common. In the coastal villages of Essex, as well as inland in Hertfordshire, the house--fronts of overlapping boards are traditionally painted black originally tarred like ships with windows and doors outlined in white. In Kent these weather boarded houses are usually white. In stone areas of Yorkshire and farther north, color is rare. the houses are usually left in their natural color, though many are painted white as they probably all were once.

单选题This passage best answers which of the following questions?

单选题There's a simple idea that two of West Germany's top car manufacturers are seriously studying at the moment, both out of self interest, but also out of concern for the environment. The concept is to develop vehicles that can run on a virtually limitless element hydrogen which when burned does not produce damaging fumes, but instead a bit of water vapour. The concept can solve two problems at once. First, it is a hedge for that day in the 21st century when hydrocarbon fuels run out, a prospect of no minor concern for the automotive industry. Beyond that, the increasingly dire warnings by environmental scientists about the "greenhouse effect" in atomosphere caused by carbon dioxide exhausts adds urgency to the quest for a fuel that is less damaging to the environment. Of course, there is a hitch to hydrogen, both carmakers admit : though the know - how to run vehicles on nature's lightest element is already available, hydrogen is far from being cost competitive compared to hydrocarbon fuels, and further refinements hydrogen - propulsion technology will be required. But what we are discussing today is the technology of the year 2020. But after several years' research Daimler and BMW engineers, in collaboration with other companies and research institutes in West Germany, independently have been tackling the technological and cost feasibility problems to be overcome in hydrogen fuel application. In addition to the two concerns of technology and economic feasibility, the carmakers say, there is the issue of safety. The spectacular explosion of the dirigible. Hindenburg in 1937 immediately comes to mind, and skeptics wonder what the German autobahn would look like in one of the hundred - car pileups that routinely happen every winter if all the cars and tanks loaded with hydrogen. A BMW engineer, Friedieh Fickel, says that hydrogen is seen as less risky than gasoline. When leaked, hydrogen rises quickly up to the atmosphere, reducing the potential of explosion, whereas gasoline fumes linger close to the ground before dispersing. Still, both Daimler and BMW report that a considerable part of their development efforts are aimed at safe, lead - free storage of hydrogen fuel. The related question is what is the best method of storage. By now, the tests by both carmakers have all but eliminated using hydrogen in gas form. As a gas it takes up about 14 times the space of liquid hydrogen and as much as 30 percent can be lost by leakage unless the tanks are perfectly sealed. Two other storage methods hold more promise. One is in liquid form, and the other in the form of metal hydrides. In the latter, hydrogen if mixed with a metal alloy, a process whereby the gas molecules are stored within the metal's molecular structure.

单选题Where lies success of a country in the New Age of Superstuff?

单选题Whatisthemainproblemcausedbytheusualwayofplowing?A.Thecrop'sbloomingperiodisdelayed.B.Therootsofcropsarecutoff.C.Thetopsoilisseriouslydamaged.D.Thegrowthofweedsisaccelerated.

单选题What does the underlined word they in Paragraph 2 refer to?