单选题The housing market has been for two years propping up consumers' spirits while the rest of the economy lies exhausted on the floor, still trying to struggle to its feet. According to the National Association of Realtors, the national median existing-home price ended the year at $164,000, up 7.1 percent from 2001. That's the strongest annual increase since 1980. Although residential real estate activity makes up less than 8% of total U. S. GDP, a housing market like this one can make the difference between positive and negative growth. Most significantly, consumer spending is 66 % of GDP, and the purchase of a new home tends to have an "umbrella effect" on the homeowner's spending as he has to stock it with a washer/ dryer, a new big-screen TV, and maybe a swing set for the yard. The main factor in housing's continued strength is a classic economic example of zero-sum boom: the persistent weakness everywhere else. As the 2003 recovery continues to be more forecast than reality. Falling stock prices raised investor appeal for U. S. Treasury Bonds, which in turn, allowed most interest rates to drift even lower. But there are not many signs that there's a bubble ready to burst. December's new record in housing starts, for example, was nicely matched by the new record in new home sales. If you build it, they will buy and even if an economic pickup starts to reduce housing's relative attractiveness, there's no reason why modest economic growth and improved consumer mood can't help sustaining housing's strength. "The momentum gained from low mortgage interest rates will carry strong home sales into 2003, with an improving economy offsetting modestly higher mortgage interest rates as the year progresses," said David Lereah, chief economist at the National Association of Realtors. Just as housing has taken up much of the economic slack for the past two years, both as a comforting investment for fretting consumers and a driver of consumer spending itself, a big bump elsewhere in the economy in 2003 could be housing's downfall. If stocks roar back this spring, capital inflows could steal from the bond market, pushing up long-term interest rates. Or Alan Greenspan and the Fed could do the same to short-term rates, as a way to hit the brakes on a recovery that is heating up too fast. In other words, if everything possible goes wrong for housing, homeowners should have plenty to compensate them in terms of job security and income hikes.

单选题Although any destruction of vitamins caused by food irradiation could be______ the use of diet supplements, there may be no protection from carcinogens that some fear might be introduced into foods by the process.

单选题Little______to win your friendship in this way.

单选题It is true that ______ you get into a bad habit, you will find it not easy to give it up.

单选题The teacher wishes to speak to you ______ your being late.

单选题Since the early eighties we have been only too aware of the devastating effects of large-scale environmental pollution. Such pollution is generally the result of poor government planning in many developing nations or the short-sighted, selfish policies of the already industrialized countries which encourage a minority of the world"s population to squander the majority of its natural resources. While events such as the deforestation of the Amazon jungle or the nuclear disaster in Chernobyl continue to receive high...remembered that not all pollution is on this grand scale. A large proportion of the world"s pollution has its source much close to home. Avoiding pollution can be a fulltime job. Try not to inhale traffic fumes, keep away from chemical plants and building-sites; wear a mask when cycling. It is enough to make you want to stay at home. But that, according to a growing body of scientific evidence, would also be a bad idea. Research shows that levels of pollutants such as hazardous gases, particulate matter and other chemical "nasties" are usually higher indoors than out, even in the most polluted cities. Since the average American spends 18 hours indoors for every hour outside, it looks as though many environmentalists may be attacking the wrong target. The latest study, conducted by two environmental engineers, Richard Corsi and Cynthia Howard-Reed, of the University of Texas in Austin, and published in Environmental Science and Technology, suggests that it is the process of keeping clean that may be making indoor pollution worse. The researchers found that baths, showers, dishwashers and washing machines can all be significant sources of indoor pollution, because they extract trace amounts of chemicals from the water that they use and transfer them to the air. Nearly all public water supplies contain very low concentrations of toxic chemicals, most of them left over from the otherwise beneficial process of chlorination. In fact, in many cases, the degree of exposure to toxic chemicals in tap water by inhalation is comparable to the exposure that would result from drinking the stuff. This is significant because many people are so concerned about water-borne pollutants that they drink only bottled water, worldwide sales of which are forecast to reach $ 72 billion by next year. Dr. Corsi"s results suggest that they are being exposed to such pollutants any way simply by breathing at home. The aim of such research is not, however, to encourage the use of gas masks when unloading the washing. Instead, it is to bring a sense of perspective to the debate about pollution. According to Dr. Corsi, disproportionate effort is wasted campaigning against certain forms of outdoor pollution; when there is as much or more cause for concern indoors, fight under people"s noses. Using gas cookers or burning candles, for example, both result in indoor levels of carbon monoxide and particulate matter that are just as high as those to be found outside, amid heavy traffic. Overcrowded classrooms whose ventilation systems were designed for smaller numbers of children frequently contain levels of carbon dioxide that would be regarded as unaccepted on board a submarine. "New car smell" is the result of high levels of toxic chemicals, not cleanliness. Laser printers, computers, carpets and paints all contribute to the noxious indoor mix. The implications of indoor pollution for health are unclear. But before worrying about the problems caused by large-scale industry, it makes sense to consider the small-scale industry, it makes sense to consider the small-scale pollution at home and welcome international debate about this. Scientists investigating indoor pollution will gather next month in Edinburgh at the Indoor Air conference to discuss the problem. Perhaps unwisely, the meeting is being held indoors.

单选题One ______ to define a republic is if a government at least derives all its powers directly or indirectly from the great body of the people.

单选题They got some valuable ______ from the night watchman.

单选题Woman : Hello, Mr. Johnson s office.Man : Good morning. __请作答此空__ ?Woman : Sorry,he s in a meeting at the moment. __57__ ?Man:Yes. This is Steve Lee from Brightlight Systems. __58___ ?Woman:

单选题The author tells us that

单选题An explanation of an earthquake is a description of the chain of ______ that produces it.

单选题Building this road will ______ the construction of ten bridges, and then the total cost reaches I million US dollars. A. evolve B. involve C. revolve D. devolve

单选题 Researchers for Cornell University and Intel produced a chip called Loihi that reportedly makes computers think like biological brains, according to Daily Mail. The researchers created the circuit on the chip, mirroring organic circuits found in the olfactory bulbs (嗅球) of a dog's brain, which is how they process their sense of smell. The Loihi chip can identify a specific odor on the first try and even tell other background smells, said Intel, according to Daily Mail. The chip can even detect smells humans emit when sick with a disease—which vary depending on the illness—and smells linked to environmental gases and drugs. The key to sniffer dogs isn't their olfactory system alone, but their incredible ability to remember—this is why they're trained. Similarly, the artificial intelligence of the chip is trained to identify different smells and remember them, so that next time, it knows. The chip processes information just like mammal brains by using electrical signals to process smells. When a person smells something, the air molecules interact with nasal receptors that forward signals to the olfactory bulb in the brain. Then the brain translates the signals to identify which smell it's experiencing, based on memories of previous experiences with the specific smell. 'We are developing a method for Loihi to mimic (模仿) what happens in your brain when you smell something,' said Senior Research Scientist in Intel's Lab, Nabil Imam, in a statement, according to Daily Mail. Imam added that the work 'demonstrates Loihi's potential to provide important sensing capabilities that could benefit various industries.' So far, the researchers have trained it on ten harmful smells. It can be installed on robots in airports to help identify hazardous objects, or integrated with sensors in power plants or hospitals to detect dangerous gases. Similar biotechnology has seen the implementation in grasshoppers recently outfitted with computer chips to sniff-out bombs. However, this negatively affects their lifespan, limiting their use. While sniffer dogs might one day be out of a job, the circuits using AI to mimic the process of smell bring us one step closer to recreating the human sensory system in artificial intelligence.

单选题The (three-fields) system is an agricultural method in which one field (out of) (three) is (left) to lie fallow while the other two fields are being cultivated.A. three-fieldsB. out ofC. threeD. left

单选题The best solution to the problem can only be found by a process of trial and ______.

单选题 Universities have started giving away their content free as 'massive open online courses', with the acronym (首字母缩略词) MOOC. Eleven top UK universities recently announced they were joining the Open University to launch FutureLearn, in a bid to catch up with the elite US institutions that have led the way in teaching huge numbers online. It all sounds great for people who, for one reason or another, can't go to a traditional university. But do MOOCs have anything to offer students who already study at a bricks-and-mortar institution, people like me who hate the niggling (烦人的) feeling that they might be missing out on a bargain? Well, I've signed up for a MOOC in microeconomics. I did it because I'm thinking about whether to do a master degree, and what to study. I'm testing my resolve: If I enjoy it enough to study in my own time, maybe I'm ready for masters. Better to find out before I hand over the money. Why else would a university student consider a MOOC? You could use it to boost CV—it shows you're motivated and you have a variety of interests and you're not struggling with your workload. And before you can use online courses to help you get a job, employers have to learn what they are and respect them. University isn't just about what you learn but proving you know it. The only proof you did your MOOC is that you clicked on 'I promise not to cheat' on the honor code. This is changing though: One of the biggest MOOC organizers, Coursera, is trialing facial recognition software to monitor students, and charging a small fee for verification. Do MOOCs pose a threat to old school universities? Should we fear that, before we've even paid them off, traditional university degrees will go the way of floppy (松软的，垂下的) disks? Probably not. As Patrick McGee writes, they are a long way from ready to replace traditional degrees. A MOOC versus traditional university mega-battle to the death is unlikely—instead online courses offer another option on higher education's menu of delights. MOOCs still have teething problems. A Coursera course—oh so ironically about planning online courses—crashed recently, unable to cope with the thousands of students trying to join online discussions. MOOCs are limited to subjects that can be assessed with multiple choice exams, marked automatically. Written any essays in your degree? Your professor's critique of them can't be replicated by a MOOC—yet. As for me, despite not making a single friend in a cohort (一批人) of 37000, I revelled in the chance to learn what I was interested in, on my own terms. MOOCs are a new take on education—and we traditional university students needn't miss out.

单选题The cultures of China and Japan have shared many features, but each has used them according to its national ______.

单选题Mr. Johnson is the head of the ______ department in this company. A．personal B．personnel C．personality D．permanent