首页 > 题库 > 外交学院
选择学校
A B C D F G H J K L M N Q S T W X Y Z

Should everyone be getting more folic acid? That’s the question on a lot of doctors’ minds. Though not as famous as vitamin C, folic acid plays a crucial role in the development of just about every cell in the body. Member of the B-vitamin family, it’s found naturally in orange juice, beans and green vegetables. There is some evidence that folic acid may reduce the risk of heart disease, but it is best known for its role in preventing spinal bifida and other birth defects. Indeed ever since 1998, when the U.S. Food and Drug Administration mandated that it be added to cereal products, the number of so-called neural-tube defects has dropped nearly 20% across America.Now comes word that the vitamin may, just may, help ward off the ravages of Alzheimer’s disease. In a study of more than 1,000 older adults published in the New England Journal of Medicine, researchers at Boston University and Tufts University found that subjects who had high levels of a particular amino acid called homocysteine in their blood were twice as likely to develop Alzheimer’s as those who didn’t. The finding is important because one of the easiest ways to lower homocysteine levels is to get plenty of folic acid.The study, although not definitive, is the strongest evidence to date that homocysteine plays a role in Alzheimer’s. Previous research had found that Alzheimer’s patients often have high levels of the amino acid in their blood-though that could be because folks with Alzheimer’s often don’t eat very well.The new study lays that explanation to rest. As part of the famous Framingham study, which has tracked the development of heart disease among residents of Framingham, Massachusetts, for more than 50 years, researchers in the 1970s started measuring the homocysteine levels of men and women who had not yet developed dementia. Those patients whose homocysteine levels measured over 14 micromoles a liter while they were still healthy were twice as likely to be diagnosed with Alzheimer’s disease later on.That doesn’t mean that if you have high homocysteine levels, you will get Alzheimer’s, or that low homocysteine levels will protect your from dementia. It’s not even certain, warns Dr. Sudha Seshadri, a neurologist at Boston University who led the study, that lowering homocysteine levels will lower the risk of Alzheimer’s. But the case for adding folic acid to your diet is getting better all the time.Of course the best source of any vitamin is a healthy diet. For those of us who still don’t eat our beans and vegetables, most multivitamins contain the recommended daily folic acid dose of 400 micrograms. (Eating four slices of enriched bread gives you the equivalent of roughly 100 micrograms.) There is no risk of overdose, although high levels of folic acid can mask the signs of pernicious anemia in people who have developed the disorder. Folic acid by itself may not keep the doctor away, but there’s no harm trying.1. Which of the following is TRUE according to the passage?2. The word “pernicious” in the last paragraph means( ).3. When did the U.S. Food and Drug Administration mandate that folic acid be added to cereal products?4. The disease of “dementia” (paragraph 4) has something to do with( ).5. Which of the following is NOT true about folic acid?

查看试题

A rapid means of long distance transportation became a necessity for the United States settlement spread ever farther westward. The early trains were impractical curiosities, and for a long time the railroad companies met with troublesome mechanical problems. The most serious ones were the construction of rails able to bear the load, and the development of a safer, effective stopping system.Once these were solved, the railroad was established as the best means of land transportation. By 1860s there were thousands of miles or railroads crossing the eastern mountain ranges and reaching westward to the Mississippi. There were also regional southern and western lines.The high point in railroad building came with the construction of the first transcontinental system. In 1862 Congress authorized two western railroad companies to build lines from Nebraska westward and from California eastward to a meeting point, so as to complete a transcontinental crossing linking the Atlantic seaboard with Pacific. The Government helped the railroads generously with money and land. Actual work on this project from California used Chinese labor, while the Union Pacific employed crews of Irish laborers. The two groups worked at remarkable speed, each trying to cover a greater distance than the other. In 1896 they met at place called Promontory in what is now the state of Utah. Many visitors came there for the great occasion. There were joyous celebrations all over the country, with parade and the ringing of church bells to honor the great achievement.The railroad was very important in encouraging westward movement. It also helped build up industry and fanning by moving raw materials and by distributing products rapidly to distant markets. In linking towns and people to one another it helped unify the United States.1. The major problems with America’s railroad system in the mid-19th century lay in( ).2. The building of the first transcontinental system( ).3. The best title for this passage would be( ).4. The construction of the transcontinental railroad took( ).5. What most likely made people think about a transcontinental railroad?

查看试题

Corporations as a group offer a variety of jobs. Most large companies send people to colleges to colleges to interview graduating students with the required academic training. A large university may have more than 500 companies a year knocking on its doors. Big firms are your best place for a job because their normal growth, employee retirements, and turnover create thousands of jobs nationwide each year.Corporations, however, illustrate the rule that the biggest isn’t always the best. Many small firms with just a few hundred employees have positions that may correspond with your profession goals, too. Such firms may not have the time, money, or need to send people around to your college; you’ll probably have to contact them yourself either directly or through an employment agency. Don’t ignore these little companies. Their salaries are usually competitive and the chances for advancement and recognition even stronger than those of a big firm. You could become a big fish in a small pond, reaching a high-level position more quickly than you would if you had climbed the most competitive ladder of a corporate giant.For example, a small company may need a bright engineering, accounting or management graduate who would report directly to the senior vice-president of engineering, the company controller, or the general manager. In larger firms it may take years to reach level and accumulate similar in-depth experience. In addition, responsibilities may come faster in a small firm with less specialization and fewer lower-level employees to receive delegated authority.1. The purpose of the passage is( ).2. Which of the following is TRUE of large corporations?3. The word “Their” (paragraph 2, line 6) refers to( ).4. Which of the following is NOT true of small firm?5. With whom is the passage most probably concerned?

查看试题

The Human Stain, directed by Robert Benton from a screenplay by Nicholas Meyer, is an honorable B+ term paper of a movie: sober, scrupulous and earnestly respectful of its literary source. This is precisely the problem: that source, Philip Roth’s 2000 novel is not especially sober, scrupulous or respectful. It is an angry, ungainly squally of a book, a clamorous defense of sexual vitality in an age of Puritan censoriousness and a lyrical inquiry into the mysteries of race, old age and recent. American history. Like much of Mr. Roth’s recent work, The Human Stain bursts with characters and ideas, and its apparently haphazard organization disguises an elegant and cunning narrative strategy.The filmmakers explicate Mr. Roth’s themes with admirable clarity and care and observe his characters with delicate fondness, but they cannot hope to approximate the brilliance and rapacity of his voice, which holds all the novels’ disparate elements together. Without the active intervention of Mr. Roth’s intelligence the story fails to cohere. Its people wander through a strangely artificial landscape, and the ideas hover in the air above them like clouds painted on a backdrop.Zuckerman played by Gary Sinise has retreated to a lakeside cabin in New England, hoping to find peace and quiet after two divorces and a bout of prostate cancer.His solitude is interrupted one night by the arrival of Coleman Silk played by Anthony Hopkins, a former dean and classics professor at nearby Athena College, who was forced to resign after being accused of making racist remarks during a lecture. Coleman, whose wife died suddenly in the wake of the scandal, wants to take revenge on his former colleagues by writing a book. He puts this project aside once he falls into a revivifying affair with Faunia Farley played by Nicole Kidman, a damaged, desolate and illiterate 34-year-old who does menial jobs at the college, the post office and a local dairy farm Their sexual idyll is menaced by the faculty busybodies who chased Coleman from his job, and also by Faunia’s former husband, Lester (Ed Harris), a deranged Vietnam veteran who sued to beat her and now stalks her in his big red pickup truck.What keeps the movie, which opens today nationwide, from drifting in the Sargasso Sea of literary high-mindedness is the vitality of the acting. Mr. Bention is the kind of director whose affection and respect for actors seep through the screen; his solicitude seems to open them up.That Mr.Hopkins and Ms. Kidman are miscast is almost axiomatic. Ms. Kidman tries to overcome this by sheer force of will, struggling to stifle her natural radiance, blunt her crystalline voice and blur her fine features, and she comes closer to succeeding than you might expect. Mr. Hopkins, for his part, must battle a more glaring discrepancy, and he does so with swinging nonchalance. Coleman Silk is a black man who has passed for white for most of his adult life, styling himself as the first Jewish classicist ever hired at Athena.These peculiarities of casting matter less than they might; or rather how much they matter changes from scene to scene. The film includes some sex, a boxing match and an occasional burst of dancing, but most of the action consists of two characters in a room talking. Some of these moments-a late confrontation between Lester and Zuckerman, a breakfast table quarrel between Faunnia and Coleman, a meeting of the minds between Faunnia and a large, caged crow-are awkwardly paced and placed, but many others are alive with human pain and heat.Some of the best performances are in secondary roles. Jacinda Barrett is wonderfully touching as Coleman’s first great love, a blond Midwesterner to whom he decides, heedlessly and a little cruelly, to divulge the secret of his race. Ms. Snuth, her face a mask of maternal stoicism, brings home the tragedy of Coleman’s decision to pass for white with a speech so drily and evenly enunciated that its lacerating insight only registers once the camera has turned away.At its beat-which also tends to be at its quietes—The Human Stain allows you both to care about its characters and to think about the larger issues that their lives represent. Its deepest flaw is an inability to link those moments of empathy and insight into a continuous drama, to suggest that the characters’ lives keep going when they are not on screen. The film’s powerful individual scenes seem like excerpts from a missing whole, well-appointed rooms in a house whose beams and girders have been cut away.1. The human Stain is a( ).2. The Human Stain( ).3. Which of the following is the flaw of The Human Stain in the author’s opinion?4. Which of the following could be a possible comment made by the author?5. The author’s attitude towards The Human Stain is( ).

查看试题

The shuttle Columbia was doomed in part because NASA relied on flawed computer simulations and mathematical formulas that failed to accurately predict damage to the shuttle from flying pieces of foam, documents released by the space agency and the group investigating the accident show.Nuclear and aviation industry safety experts who are familiar with the sorts of analyses NASA used say space agency officials were wrong to rely on the simulations to gauge risks. Instead, the experts say, they should have performed tests on shuttle components to determine the damage that foam from the fuel tank might do to its wing.These simulations and formulas some done before the launch, others done during the mission often were based on erroneous assumptions about the ability of the shuttle to withstand damage. NASA managers assumed it was safe for Columbia to return to Earth even though foam had struck the wing.The foam hit the left wing 82 seconds after liftoff and broke through one of the carbon panels designed to protect the wings from the intense heat of re-entry. Columbia broke apart as it re-entered Earth’s atmosphere on Feb.1. All seven astronauts were killed.Today, the Columbia Accident Investigation Board Will issue its findings on what caused the accident. In addition to detailing how the blow from the foam led to the break-up, the board will document how decisions by NASA managers underestimated the peril Columbia faced and how they ignored warnings, according to previous public statements from board members.The independent board’s report also is expected to find that the NASA safety office was ineffective and underfunded.Among the areas to be discussed is NASA’s reliance on computer simulations and mathematical models. Before the mission—and again after fuzzy photos showed the foam had hit Columbia’s wing-simulations and other analyses led to poor decisions by NASA managers, documents show. The simulations appear to have blinded them to danger signals about foam on earlier flights and led them to dramatically underestimate the threat to Columbia. The independent board’s report also is expected to find that the NASA safety office was ineffective and underfunded.In one case, during the Columbia mission, at least 75 shuttle experts with NASA and its contractors were so concerned about the poor quality of data in an analysis they were preparing that they recommended taking photos of the shuttle in space, sources say. Those photos could have shown whether foam had damaged the left wing.Instead, NASA managers trusted the analysis that the experts said was so flawed. The analysis wrongly estimated where the foam hit and concluded that the shuttle had not sustained significant damage. Had NASA known the extent of the damage, the agency might have launched a rescue mission to try to save Columbia’s crew.Engineers connected to the analysis say they are angry and puzzled that NASA would not seek photos from satellites or telescopes. NASA managers say they were not told of the limitations on computer simulations and analyses.By necessity, NASA relies heavily on computer models and other analysis tools to provide clues about what happens to the shuttle from launch until re-entry. It cannot easily recreate the extreme temperatures of space in a lab. Used properly, such analyses can improve safety. Indeed, analysis techniques routinely help design safer jet wings and nuclear plants.But safety experts in high-risk industries say they’ve learned the hard way mathematical formulas and computer simulations cannot fully mimic nature. Several major aviation crashes and the Three Mile Island nuclear accident were caused by poor analyses, experts say.“You need to take into account the uncertainties” says Elizabeth Pate-Cornell, chairman of the management sciences and engineering department at Stanford University. “It’s the old story: garbage in, garbage out.”As Columbia orbited, engineers erroneously concluded the foam could not damage the wing’s carbon panels. The analysis was based on earlier tests of small ice pellets hitting the panels. But those tests could not predict whether a large chunk of foam would cause damage.A computer program known as Crater, which engineers used to predict whether the foam damaged the ceramic tiles beneath Columbia’s wing, had not been designed to account for impacts from large pieces of foam.1. Nuclear and aviation safety experts( ).2. In the authors opinion, NASA managers( ).3. The Columbia Accident Investigation Board will issue its findings with regard to the following EXCEPT( ).4. NASA managers made poor decisions because they did NOT( ).5. Safety experts in high-risk industries indicate that computer simulations( ).

查看试题

I quiz myself once in a while: How many official South African languages can I name? There are eleven-Afrikaans, English, Ndebele, Pedi, Sotho, Swazi, Tsonga, Tswana, Venda, Xhosa, and Zulu—but I usually get(1)around six or seven. I often wonder how the South African government can(2)them all. It turns out that they really can’t.Many languages are regulated by some kind of authority, such as Spain’s Real Academia Espanola (a government body) or France’s Academie Francaise (more of an outside advisor). South Africa’s eleven languages are all regulated by the chronically underfunded Pan South African Language Board, a governmental department. English is in no danger, of course. Afrikaans is mostly regulated by a separate body. As a result, PanSALB concerns itself mostly(3)the nine official Bantu languages, as well as Khoi, San and South African Sign Language.I wrote last week that literature in southern African languages is(4)before ever having a chance to be(5). Yes, there are social and historical reasons why literature development has been(6). But some blame rests(7)PanSALB, the sole institution dedicated to these languages. It is repeatedly accused of corruption and mismanagement. During a recent inquiry, it was uncooperative. The parliament’s culture committee has voted to reduce funding for PanSALB until it “got its house in(8)”, after wondering aloud in April how its budget of 56m rand ($6. 9m) produced so little. Thandile Sunduza, the chairwoman of the committee, thinks it best to eliminate PanSALB altogether, saying in May “There is nothing that has been done-no program, nothing, any money. There is nothing.”To be sure, mismanagement is(9)in South Africa’s government. Even if PanSALB were able to produce textbooks in, say, Pedi, recent events suggest that they would never(10)it to Pedi-speaking students in Limpopo province. But for infant literatures, PanSALB’s incompetence could be fatal. PanSALB is the only major funding and support lifeline for many South African languages.

查看试题

暂未登录

成为学员

学员用户尊享特权

老师批改作业做题助教答疑 学员专用题库高频考点梳理

本模块为学员专用
学员专享优势
老师批改作业 做题助教答疑
学员专用题库 高频考点梳理
成为学员