单选题The two main causes are population pressures, especially the pressures (of) large metropolitan populations, and the desire—a (highly) commendable one—to bring a decent (life) at the lowest possible cost to the (largest) possible number of people.

单选题Since the price you quoted would leave us no margin of ______, we must do business with other suppliers who are offering lower prices for Dinner Sets of the same quality.

单选题Two decades ago only spies and systems administrators had to worry about passwords. But today you have to enter one even to do humdrum things like turning on your computer, downloading an album or buying a book online. No wonder many people use a single, simple password for everything. Analysis of password databases, often stolen from websites, shows that the most common choices include "password", "123456" and "abc123". But using these, or any word that appears in a dictionary, is insecure. Even changing some letters to numbers ("e" to "3", "i" to "1" and so forth) does little to reduce the vulnerability of such passwords to an automated "dictionary attack", because these substitutions are so common. The fundamental problem is that secure passwords tend to be hard to remember, and memorable passwords tend to be insecure. Weak passwords open the door to fraud, identity theft and breaches of privacy. An analysis by Verizon, an American telecoms firm, found that the biggest reason for successful security breaches was easily guessable passwords. Some viruses spread by trying common passwords. The solution, say security researchers, is to upgrade the software in people's heads, by teaching them to choose more secure passwords. One approach is to use passphrases containing unrelated words, such as "correct horse battery staple", linked by a mental image. Passphrases are, on average, several orders of magnitude harder to crack than passwords. But a new study by researchers at the University of Cambridge finds that people tend to choose phrases made up not of unrelated words but of words that already occur together, such as "dead poets society" . Such phrases are vulnerable to a dictionary attack based on common phrases taken from the Internet. And many systems limit the length of passwords, making a long phrase impractical. An alternative approach, championed by Bruce Schneier, a security guru, is to turn a sentence into a password, taking the first letter of each word and substituting numbers and punctuation marks where possible. "Too much food and wine will make you sick" thus becomes "2mf&wwmUs". This is no panacea: the danger with this "mnemonic password" approach is that people will use a proverb, or a line from a film or a song, as the starting point, which makes it vulnerable to attack. Some websites make an effort to enhance security by indicating how easily guessed a password is likely to be, rejecting weak passwords, ensuring that password databases are kept properly coded and limiting the rate at which login attempts can be made. More should do so. But don't rely on it happening. Instead, beef up your own security by upgrading your brain to use mnemonic passwords.

单选题How and why would strain and anxiety trigger some of us to pile on extra weight? Stress activates the flight-or-fight response (应激反应), a physiological reaction designed to get your body moving quickly in a physical emergency. When your brain perceives a threat, it sounds the alarm to your adrenal glands (肾上腺) to pump out the stress hormone cortisol (皮质醇). The hormone then signals fat cells to quickly release energy, which your muscles can use for a surge of power to "flee" or "fight". When the danger passes, cortisol briefly stays elevated to encourage your body to replenish (补充) its fat stores, then returns to normal. "The system works beautifully if you're running for the last bus home after work. It gives you a burst of energy, which you recover from quickly once you take your seat," says Pamela Peeke, MD, clinical assistant professor of medicine and author of Body for Life for Women. But when you turn on the stress response for months on end—worrying about your marriage or mortgage payments—you do damage. "Then, cortisol levels remain persistently elevated, persistently signaling your body to store fat," says Dr. Peeke. This mechanism may also affect where flab (松弛) builds up on your body. Under stress, women who carry excess weight in their abdominal area secreted (分泌) significantly more cortisol than women who didn't have extra belly fat, according to a study from the University of California at San Francisco. And since deep abdominal fat tissue has up to four times the number of receptors for cortisol as does superficial fat elsewhere in the body, the cells in this area are the most likely to respond and store fat when exposed to extra stress-induced cortisol. Unfortunately, this extra abdominal flab isn't just a cosmetic concern; it is strongly linked to a greater risk of heart disease and stroke, two top killers of women over 50. The cumulative (累积的) effects of the stress-fat connection can be great. Although you can't control many of the things that cause you stress, you can take steps to curb the negative effect these stressors have on your body. "Support is essential. Reach out to family and friends," says Alice Domar, PhD, director of the Mind/Body Center for Women's Health at Boston IVF.

单选题The commissioner of a professional sports league dictated that teams could not put players on the field who had a greater than 20 percent chance of suffering a career-ending spinal injury during competition. The commissioner justified this decision as a way to protect players from injury while protecting the league from lawsuits. Which of the following, if true, would most undermine the effectiveness of the commissioner's new policy? A. Spinal injuries can result in paralysis, loss of fine motor skills, and even death. B. The previous year, more than seven players in the league suffered career-ending spinal injuries. C. The players' union agrees that the risk of injury is an inevitable part of playing the game at a professional level. D. There is no scientifically valid method for determining the likelihood of any player suffering a career-ending spinal injury at any given time. E. Players barred from playing because of this new regulation will be entitled to compensation for lost wages at a level determined by the commissioner's office.

单选题When ______ ,the museum will be open to the public next year. A. completed B. completing C. being completed D. to be completed

单选题I think I was at school, ______ I was staying with a friend during the vacatizon when I heard the news． A．or else B．and then C．or so D．even so

单选题The children ______ around their grandmother. A. were seated B. seat C. was seated D. seated

单选题It is natural for young people to be critical of their parents ______ .

单选题The teacher insisted that we ( ) our homework before 9 o'clock.

单选题In 1976 Sarah Caldwell became______at the Metropolitan Opera House in New York City.

单选题If sustainable competitive advantage depends on work force skills, American firms have a problem. Human management is not traditionally seen as central to the competitive survival of the firm in the United States. Skill acquisition is considered as individual responsibility. Labor is simply another force of production to be hired/rented at the lowest possible cost, which is a must as one buys raw material or equipment. The lack of importance attached to human resource management can be seen in the corporate pecking order. In an American firm the chief financial officer is almost always second in command. The post of head of human resource management is usually a specialized job, off at the edge of the corporate hierarchy. The executive who holds it is never consulted on major strategic decisions and has no chance to move up to Chief Executive Officer. By way of contrast, in Japan the head of human resource management is central—usually the second most important executive, after the CEO, in the firm's hierarchy. While American firms often talk about the vast amounts spent on training their work force, in fact, they invest less in the skills of their employees than do either Japanese or German firms. The money they do invest is also more highly concentrated on professional or managerial employees. And the limited investments that are made in training workers are also much more narrowly focused on the specific skills necessary to do the next job rather than on the basic background skills that make it possible to absorb new technologies. As a result, problems emerge when new breakthrough technologies arrive. If American workers, for example, take much longer to learn how to operate new flexible manufacturing stations than workers in Germany (as they do), the effective cost of those stations is lower in Germany than it is in the United States. More time is required before equipment is up and running at the speed with which new equipment is up and running at capacity, and the need for extensive retraining generates costs and creates bottlenecks that limit the speed with which new equipment can be employed. The result is a slower pace of technological change. And in the end the skills of the bottom half of the population affect the wages of the top half. If the bottom half can't effectively staff the processes that have to be operated, the management and professional jobs that go with these processes will disappear.

单选题The children ______ very quiet; I wonder what they ______ up to.A. were; are beingB. are being; areC. are; doD. are being; do

单选题The attack was meticulously planned and executed. A. negligently B. slovenly C. fussily D. discreetly

单选题Companies that employ illegal immigrants are to be named and shamed in a further attempt to crack down on people smuggling. The move by the Home Office comes four months after officials launched a concerted effort to identify and prosecute companies breaking the law. More than 200 companies have already been fined for hiring illegal labor. The Home Office says names of companies and directors are to be published on the UK Border Agency website. The agency will publish how many illegal immigrants the company was employing and how much it was fined. By May this year there had been 137 prosecutions under the new rules leading to fines totaling 500,000—almost 3,000 per firm. The total number of prosecutions was 10 times more than were carried out in 2007, and double the total for the previous decade. Immigration chiefs are also switching their focus from small-time illegal employers, such as takeaway restaurants, in an effort to major organized criminal enterprises supplying illegal labor, often relying on international networks to smuggle people into the UK. Some 7,500 immigration officers will be re-organized into more localized teams with police and customs officials in an effort to better target what the Home Office says are illegal working hotspots. These could include areas of the economy where there is a high demand for labor including agriculture, construction and hospitality. Nobody knows how many people are working without permission in the UK—although estimates put the number of illegal residents at more than 500,000. Trade Union leaders have also raised concerns about the government's strategy, arguing that it could drive the worst employers further underground, penalizing exceptionally poor workers unable to break out of a situation they did not necessarily choose.

单选题Pat. Sorry, Linda, I'm late. It took me ages to find parking. Linda：______ A. Did you have a good time there? B. Did you find the park? C．We’ve got too many cars nowadays． D. I found paking just a few minutes ago．