单选题The policeman saw the thief ______ he appeared on the street corner. A) not until B) as long as C) the moment D) only if

单选题When global warming finally came, it stuck with a vengeance. In some regions, temperatures rose several degrees in less than a century. Sea levels shot up nearly 400 feet, flooding coastal settlements and forcing people to migrate inland. Deserts spread throughout the world as vegetation shifted drastically in North America, Europe and Asia. After driving many of the animals around them to near extinction, people were forced to abandon their old way of life for a radically new survival strategy that resulted in widespread starvation and disease. The adaptation was farming: the global-warming crisis that gave rise to it happened more than 10,000 years ago. As environmentalists convene in Rio de Janeiro this week to ponder the global climate of the future, earth scientists are in the midst of a revolution in understanding how climate has changed in the past—and how those changes have transformed human existence. Researchers have begun to piece together an illuminating picture of the powerful geological and astronomical forces that have combined to change the planet"s environment from hot to cold, wet to dry and back again over a time period stretching back hundreds of millions of years. Most important, scientists are beginning to realize that the climatic changes have had a major impact on the evolution of the human species. New research now suggests that climate shifts have played a key role in nearly every significant turning point in human evolution: from the dawn of primates some 65 million years ago to human ancestors rising up to walk on two legs, from the huge expansion of the human brain to the rise of agriculture. Indeed, the human history has not been merely-touched by global climate change, some scientists argue, it has in some instances been driven by it. The new research has profound implications for the environmental summit in Rio. Among other things, the findings demonstrate that dramatic climate change is nothing new for planet Earth. The benign global environment that has existed over the past 10,000 years—during which agriculture, writing, cities and most other features of civilization appeared—is a mere bright spot in a much larger pattern of widely varying climate over the ages. In fact, the pattern of climate change in the past reveals that Earth"s climate will almost certainly go through dramatic changes in the future—even without the influence of human activity.

单选题— How do you ______ we go to Beijing for our Holidays? — I think we'd better fly there. It's much comfortable.A. insistB. wantC. supposeD. suggest

单选题Democrats on the Senate Judiciary Committee vented their fury over high gasoline prices at executives of the nation"s five largest oil companies on Wednesday, grilling the oilmen over their multimillion-dollar pay packages and warning them that Congress was intent on taking action that could include a new tax on so-called windfall profits. Such showdowns between lawmakers and oil titans have become a familiar routine on Capitol Hill. But with gas prices nearing $ 4 a gallon, and lawmakers headed home for a weeklong Memorial Day recess where they expect to get an earful from angry constituents, there is added urgency for Congress to appear active. But while momentum is building for several measures, including a bill that would allow the Organization of the Petroleum Exporting Countries to be sued in American courts under antitrust laws, there is little sign that any of the proposals would do much, if anything, to lower prices quickly. And the oil executives warned that government intervention might only make things worse. Instead, they called on Congress to allow more drilling and exploration for domestic oil. The increasing urgency to seem aggressive about gasoline prices was apparent on Tuesday when the House voted by an overwhelming 324 to 84 to approve the bill, commonly referred to as NOPEC, which classifies OPEC as a monopoly in violation of the Sherman Antitrust Act. Senate Democrats have included that measure as part of a package of legislation intended to address the high price of gasoline, along with the tax on windfall profits and a measure to tamp down speculation in the oil futures market that many lawmakers think is contributing to the run-up in prices. At the Judiciary Committee hearing, Democratic senators struggled to have the executives explain how oil prices had risen so high. The senators expressed doubt that basic laws of supply and demand were at work and suggested instead a more sinister combination of monopolistic behavior by oil-producing countries, speculation in the futures markets and sheer corporate greed. On Monday, President Bush signed a bill temporarily suspending the purchase of crude oil for the nation"s Strategic Petroleum Reserve. Mr. Bush had initially opposed such action but relented after the House and Senate approved the bill by wide margins. Senator Richard J. Durbin, Democrat of Illinois and a strong supporter of Senator Baraek Obama"s presidential bid, made a particularly pointed attack, in which he seemed to warn the oil executives that they would soon no longer have such a good friend in the White House. He also suggested that Mr. Bush should be doing more to press the oil companies to help lower prices at the pump, while acknowledging that it would be difficult to pass a windfall profits tax while Mr. Bush was still in office.

单选题In some remote places, there are still very poor people who can't afford to live in ______ conditions. A. positive B. gracious C. honorable D. decent

单选题Since time immemorial, countless scholars have asked the question: What is beauty? As philosophers engage in weighty discourses, designers update the latest fashions, and artists create their masterpieces, what is considered beautiful changes at an alarming pace. Fifty years ago, the full-figured Marilyn Monroe embodied the American aesthetic value; today, a legion of Hollywood actresses vastly different in appearance from Marilyn"s have taken her place. However, aesthetic values not only differ from generation to generation, but do so along cultural lines as well. The conventions that govern painting and music vary greatly from East to West. Often, what is considered disgusting to one civilization is the pinnacle of aesthetic appeal in another. Thus, when left to the sphere of human design, the search for an absolute definition of beauty remains an elusive one at best. As fundamental physicists, my colleagues and I like to believe that we are involved in a search for a beauty that does not remain uninfluenced by definition; The beauty that we search for is not that which is laid down through the work of people and subject to short-term tastes, but rather that which has been established by Nature. Those not involved with physics tend to think of it as a precise and predictive science—certainly not a field of study fit for the contemplation of the beautiful. Yet, one of physics"s greatest gifts is that it allows its students to look past extrinsic appearances into a more overwhelming beauty. As a human being, I am captivated by the visual appeal of a wave crashing on the beach. As a physicist, however, I possess the ability to be captivated by the much deeper beauty of the physical laws that govern such a phenomenon. Where the nonphysicist sees a lovely but inexplicable event, the well-schooled physicist is able to perceive a brilliant design. In truth, since the day that Albert Einstein first proposed the notion that there might be one overarching physical theory that governs the universe, aesthetics has become a driving force in modern physics. What Einstein and we, as his intellectual descendants, have discovered is this;Nature, at its most fundamental level, is beautifully constructed. The remarkable simplicity of the laws that govern the universe is, at times, nothing short of breathtaking. And at every step, as new discoveries and technologies allow us to examine the physical world on deeper and deeper levels, we find that the beauty itself becomes more profound. As Einstein himself said, it would seem more likely that we should find ourselves living in a " chaotic world, in no way graspable through thinking. " Yet here we are, closer than ever to a full understanding of the universe"s beautiful clockwork.

单选题A ______ contest is intended to eliminate less qualified competitors before decisive contests.

单选题I don't know ______ talking about.

单选题— May I go and play football with Dick this afternoon, Dad? — No, you can't go out ______ your work is being done.A. beforeB. untilC. asD. after

单选题As they grow older, most people wonder how increasing age will affect intelligence. Can people in middle age and beyond expect to think as effectively and to solve problems as efficiently as they have in the past? One of the difficulties in comparing the intellectual functioning of people at different ages is the problem of cohort((具有相同特征的)一群人) effects. Different age groups in the population have experienced different historical events (wars, exposure to television, and so on) as well as changes in the general standard of living. Different scores that people of varying ages achieve on intelligence tests could be partly due to changes in diet, housing, or health care or, even more likely, to the amount and quality of education. Since the beginning of this century, there has been a trend for more people to go to school and to remain in school longer. Because it eliminates these cohort effects, a longevous (长寿的) study may be the best way to look at age-related changes in intellectual functioning. One of the few longevous studies of intellectual functioning is the Seattle Longevous Study, conducted by K. Warner Schaie and his associates. The original subjects, who ranged in age from 18 to 67, have now been tested 4 times over a 21 year period. These results have given a reasonably good picture of longitudinal(纵向的) change in cognitive abilities. The data show that there are only trivial changes in the kinds of abilities measured by intelligence tests before the age of 60, and no reliable decrease can be shown in these abilities before age 74. Although there is some decrease in measured ability in the late 60s and the 70s, it is not until age 81 that the average person falls below the middle range of performance for young adults. The data from the Seattle Longevous Study also suggest that there are very great individual differences in intellectual change throughout adulthood. Between the ages of 74 and 81, less than half the subjects showed any significant change. One important factor is health, especially the presence or absence of coronary(冠状) heart disease. Another is a high socioeconomic status, which is related not only to higher initial levels of functioning but to the maintenance of a higher level throughout life. A flexible life style in middle age, probably associated with a flexible personality style, also tends to predict high performance in old age. While some of these variables may have substantial hereditary (遗传的) elements, changes in environment and education could also be important in maintaining a higher level of functioning for many individuals.

单选题Respect for the law is the foundation of civilized living, ______breaks it will be punished.

单选题Can the Internet help patients jump the line at the doctor's office? The Silicon Valley Employers Forum, a sophisticated group of technology companies, is launching a pilot program to test online "virtual visits" between doctors at three big local medical groups and about 8, 000 employees and their families. The six employers taking part in the Silicon Valley initiative, including heavy hitters such as Oracle and Cisco Systems, hope that online visits will mean employees won't have to skip work to tend to minor ailment or to follow up on chronic conditions. "With our long commutes and traffic, driving 40 miles to your doctor in your hometown can be a big chunk of time, " says Cindy Conway, benefits director at Cadence Design Systems, one of the participating companies. Doctors aren't clamoring to chat with patients online for free; they spend enough unpaid time on the phone. Only 1 in 5 has ever E-mailed a patient, and just 9 percent are interested in doing so, according to the research firm Cyber Dialogue. "We are not stupid, " says Stirling Somers, executive director of the Silicon Valley Employers group. "Doctors getting paid is a critical piece in getting this to work. " In the pilot program, physicians will get $ 20 per online consultation, about what they get for a simple office visit. Doctors also fear they'll be swamped by rambling E-mails that tell everything but what's needed to make a diagnosis. So the new program will use technology supplied by Healinx, an Alameda, Calif. -based start-up. Healinx's "Smart Symptom Wizard" questions patients and turns answers into a succinct message. The company has online dialogues for 60 common conditions. The doctor can then diagnose the problem and outline a treatment plan, which could include E-mailing a prescription or a face to face visit. Can E-mail replace the doctor's office? Many conditions, such as persistent cough, require a stethoscope to discover what's wrong—and to avoid a malpractice suit. Even Larry Bonham, head of one of the doctor's groups in the pilot, believes the virtual doctor's visits offer a "very narrow" sliver of service between phone calls to an advice nurse and a visit to the clinic. The pilot program, set to end in nine months, also hopes to determine whether online visits will boost worker productivity enough to offset the cost of the service. So far, the Internet's record in the health field has been underwhelming. The experiment is "a huge roll of the dice for Healinx, " notes Michael Barrett, and analyst at Internet consulting from Forester Research. If the "Web visits" succeed, expect some HMOs (Health Maintenance Organizations) to pay for online visits. If doctors, employers, and patients aren't satisfied, figure on one more E-health start-up to stand down.

单选题The author seems to agree that

单选题You ______ her in her office last Friday；shes been out of town for two weeks． A) neednt have seen B) must have seen C) might have seen D) cant have seen

单选题As an interdisciplinary study of language use, ______ attempts to show the relationship between language and society.

单选题Many teachers believe that the responsibility for learning lies with the student. If a long reading assignment is given, teachers expect students to be familiar with the information in the reading even if they do not discuss it in class or give an examination. The ideal student is considered to be one who is motivated to learn for the sake of learning, not the one only interested in getting high grades. When research is assigned, the professor expects the student to take the initiative and to complete the assignments with minimal guidance. Professors will help students who need it, but prefer that their students not be overly dependent on them. In the United States, professors have other duties besides teaching. Often they are responsible for administrative work within their departments. In addition, they may be obliged to publish articles and books. Therefore, the time that a professor can spend with a student outside of class is limited. If a student have problems with classroom work, the student should either approach a professor during office hours or make an appointment. Participation in the classroom is not only accepted but also expected of the students in many courses. Some professors base part of the final grade on the student's oral participation. Although there are formal lectures during which the student has a passive role ( i. e. listening and taking notes) many courses are organized around classroom discussions, students questions, and informal lectures. In the teaching of science and mathematics , the dominant mode of instruction is generally traditional, with teachers presenting formal lectures and students taking notes. However, new educational , sociology, and psychology classes, for example, are often required to solve problems in groups, design projects, make presentations and examine case studies. Since some college or university courses are"applied" rather than theoretical, they stress "doing"and involvement.