单选题We were {{U}}astonished{{/U}} to hear that their football team had won the champion. A.amazed B.amounted C.amused D.approached

单选题The cylindrical shape of a cactus {{U}}reduces{{/U}} moisture loss.

单选题The first navigational lights in the New World were probably lighthouses hung at harbor entrances. The first lighthouse was put up by the Massachusetts Bay Colony in 1716 on Little Brewster Island at the entrance to Boston Harbor. Paid for and maintained by "light dues" levied (征收) on ships, the original beacon was blown up in 1776. Until then there were only a dozen or so true lighthouses in the colonies. Little over a century later, there were 700 lighthouses. The first eight lighthouses erected on the West Coast in the 1850s featured the same basic New England design: a Cape Cod dwelling with the tower rising from the center or standing close by. In New England and elsewhere, though, lighthouses reflected a variety of architectural styles. Since most stations in the Northeast were set up on rocky eminences (高处), enormous towers were not the rule. Some were made of stone and brick, others of wood or metal. Some stood on pilings or stilts; some were fastened to rock with iron rods. Farther south, from Maryland through the Florida Keys, the coast was low and sandy. It was often necessary to build tall towers there—massive structures like the majestic lighthouse in Cape Hatteras, North Carolina, which was lit in 1870. 190 feet high, it is the tallest brick lighthouse in the country. Not withstanding differences in construction appearance, most lighthouses in America shared several features: a light, living quarters, and sometimes a bell (or, later, a foghorn). They also had something else in common: a keeper and usually the keeper"s family. The keeper"s essential task was trimming the lantern wick (灯芯) in order to maintain a steady, bright flame. The earliest keepers came from every walk of life, they were seamen, farmers, mechanics, rough mill hands and appointments were often handed out by local customs commissioners as political plums. After the administration of lighthouse was taken over in 1852 by the United States Lighthouse Board, and agency of the Treasury Department, the keeper corps gradually became highly professional.

单选题The Need to Remember Some people say they have no memory at all: "I just can"t remember a thing!" But of course we all have a memory. Our memory tells us who we are. Our memory helps us to make use in the present of what we have learnt in the past. In fact we have different types of memory. For example, our visual memory helps us recall facts and places. Some people have such a strong visual memory that they can remember exactly what they have seen, for example, pages of a book, as a complete picture. Our verbal(言语的) memory helps us remember words and figures we may have heard but not seen or written: Items of a shopping list, a chemical formula, dates, or a recipe. With our emotional(情感的)memory, we recall situations or places where we had; strong feelings, perhaps of happiness or unhappiness. We also have special memories for smell, taste, touch and sound, and for performing physical movements. We have two ways of storing any of these memories. Our short-term memory stores items for up to thirty seconds—enough to remember a telephone number while we dial. Our long-term memory, on the other hand, may store items for a lifetime. Older people in fact have a much biter long-term memory than short-term. They may forget what they have done only a few hours ago, but have the clearest remembrance(记忆) of when they were very young. Psychologists tell us that we only remember a few facts about our past, and that we invent the rest. It is as though we remember only the outline of a story. We then make up the details. We often do this in the way we want to remember them, usually so that we appear as the heroes of our own past, or maybe victims needing sympathy (同情).

单选题{{B}}第二篇{{/B}} {{B}}Late-Night Drinking{{/B}} Coffee lovers beware. Having a quick "pick-me-up" cup of coffee late in the day will play havoc with your sleep. As well as being a stimulant, caffeine interrupts the flow of melatonin, the brain hormone that sends people into a sleep. Melatonin levels normally start to rise about two hours before bedtime. Levels then peak between 2 am and 4 am, before falling again. "It's the neurohormone that controls our sleep, and tells our body when to sleep and when to wake," says Maurice Ohayon of the Stanford Sleep Epiderniology Research Center at Stanford University in California. But researchers in Israel have found that caffeinated coffee halves the body's levels of this sleep hormone. Lotan Shilo and a team at the Sapir Medical Center in Tel Aviv University found that six volunteers slept less well after a cup of caffeinated coffee than after drinking the same amount of decal On average, subjects slept 336 minutes per night after drinking caffeinated coffee, compared with 415 minutes after decaf. They also took haft an hour to drop off--twice as long as usual -- and jigged around in bed twice as much. In the second phase of the experiment, the researchers woke the volunteers every three hours and asked them to give a urine sample. Shilo measured concentrations of a breakdown product of melatonin. The results suggest that melatonin concentrations in caffeine drinkers were half those in decaf drinkers. In a paper accepted for publication in Sleep Medicine, the researchers suggest that caffeine blocks production of the enzyme that drives melatonin production. Because it can take many hours to eliminate caffeine from the body, Ohayon recommends that coffee lovers switch to decaf after lunch.

单选题The Industrial Revolution marked the beginning of an {{U}}epoch{{/U}} of exodus from rural areas to cities.

单选题Man cannot exit without water.

单选题The label on the packet read: "This product contains no Uartificial/U colouring or flavouring."

单选题A task for future scientists is to find out how an animal receives a warning signal.

单选题Customers often defer payment as long as possible. A. make B. demand C. obtain D. postpone

单选题Your dog needs at least 20 minutes of {{U}}vigorous{{/U}} exercise every day. A. energetic B. free C. physical D. regular

单选题The city of New Orleans showed its appreciation for Eleanor McMain's work in social reform by giving her the Times-Picayune award for out-standing service in 1920.

单选题2. Finding Yourself without GPS As more mobile phones tap into the Internet, people increasingly turn to them for location-centric services like getting directions and finding nearby restaurants. While Global Positioning System (GPS) technology provides excellent accuracy, only a fraction of phones have this capability. What's more, GPS coverage is spotty in dense urban environments, and in—phone receivers can be slow and drain a phone's battery. To sidestep this problem, last week Google added a new feature, called My Location, to its Web-based mapping service. My Location collects information from the nearest cell-phone tower to estimate a person's location within a distance of about 1,000 meters. This resolution is obviously not sufficient for driving directions, but it can be fine for searching for a restaurant or a store. "A common use of Google Maps is to search nearby," says Steve Lee, product manager for Google Maps, who likened the approach to searching for something within an urban zip code, but without knowing that code. "In a new city, you might not know the zip code, or even if you know it, it takes time to enter it and then to zoom in and pan around the map." Many phones support software that is able to read the unique identification of a cell-phone tower and the coverage area that surrounds it is usually split into three regions. Lee explains that My Location uses such software to learn which tower is serving the phone—and which coverage area the cell phone is operating in. Google also uses data from cell phones in the area that do have GPS to help estimate the locations of the devices without it. In this way, Google adds geographic information to the cell—phone tower's identifiers that the company stores in a database. As the database grows, says Lee, the service will become more accurate. It will never be as accurate as GPS, but he expects that it could eventually find a person within a couple hundred meters.

单选题Shyness is the cause of much unhappiness for a great many people. Shy people are anxious and selfconscious; that is, they are excessively concerned with their own appearance and actions. Worrisome thoughts are constantly occurring in their minds. What kind of impression am I taking? Do they like me? Do I look stupid? Am I wearing attractive clothes? It is obvious that such uncomfortable feelings must affect people adversely. A person's self-concept is reflected in the way he or she behaves, and the way a person behaves affects other people's reactions. In general, the way people think about themselves has a profound effect on all areas of their lives. Shy people, having low self-esteem, are likely to be passive and easily influenced by others. They need reassurance that they are doing "the right thing". Shy people are very sensitive to criticism; they feel it confirms their inferiority. They also find it difficult to be pleased by compliments because they believe they are unworthy of praise. A shy person may respond to a compliment with a statement like this one, "you are just saying that to make me feel good. I know it's not true." It is clear that, while self-awareness is a healthy quality, overdoing it is harmful. Can shyness be completely eliminated, or at least reduced? Fortunately, people can overcome shyness with determined and patient effort in building self-confidence. Since shyness goes hand in hand with lack of self-esteem, it is important for people to accept their weaknesses as well as their their strengths. For example, most people would like to be "A" student in every subject. It is not fair for them to label themselves inferior because they have difficulty in some areas. People's expectations of themselves must be realistic. Living on the impossible leads to a sense of inadequacy. Each one of us is a unique, worthwhile individual. We are interested in our own personal ways. The better we understand ourselves, the easier it becomes to live up to our full potential. Let's not allow shyness to block our chances for a rich and fullfilling life.

单选题 The Threat to Kiribati The people of Kiribati are afraid that one day in the not-too-distant future, their country will disappear from the face of the earth-literally. Several times this year, the Pacific island nation has been flooded by a sudden high tide. These tides, which swept across the island and destroyed houses, came when there was neither wind nor rain. "This never happened before, "say the older citizens of Kiribati. What is causing these mysterious high tides? The answer may well be global warming. When fuels like oil and coal are being burned, pollutants (污染物)are released; these pollutants trap heat in the earth's atmosphere. Warmer temperatures cause water to expand and also create more water by melting glaciers (冰川)and polar (极地的) ice caps. If the trend continues, scientists say, many countries will suffer. Bangladesh, for example, might lose one-fifth of its land. The coral (珊瑚) island nations of the Pacific, like Kiribati and the Marshall Islands, however, would face an even worse fate—they would be swallowed by the sea. The loss of these coral islands would be everyone's loss. Coral formations are home to more species than any other place on earth. The people of these nations feel frustrated. The sea, on which their economies have always been based, is suddenly threatening their existence. They don't have the money for expensive technological solutions like seawalls. And they have no control over the pollutants, which are being released mainly by activities in large industrialized countries. All they can do is to hope that industrialized countries will take steps to reduce pollution.

单选题Many transmitter towers were built

单选题{{B}}第三篇{{/B}} {{B}}Winged Robot Learns to Fly{{/B}} Learning how to fly took nature millions of years of trial and error --but a winged robot has cracked it in only a few hours, using the same evolutionary principles. Krister Wolff and Peter Nordin of Chalmers University of Technology (CUT) in Gothenburg, Sweden, built a winged robot and set about testing whether it could learn to fly by itself, without any pre-programmed data on what flapping is or how to do it. To begin with, the robot just twitched and jerked erratically. But, gradually, it made movements that gained height. At first, it cheated -- simply standing on its wing tips was one early short cut. After three hours, however, the robot abandoned such methods in favor of a more effective flapping technique, where it rotated its wings through 90 degrees and raised them before twisting them back to the horizontal and pushing down. "This tells us that this kind of evolution is capable of coming up with flying motion," says Peter Bentley, who works on evolutionary computing at University College London. But while the robot had worked out how best to produce lift, it was not about to take off. "There's only so much that evolution can do," Bentley says. "This thing is never going to fly because the motors will never have the strength to do it," he says. The robot had metre-long wings made from balsa wood and covered with a light plastic film. Small motors on the robot let it move its wings forwards or backwards, up or down or twist them in either direction. The team attached the robot to two vertical rods, so it could slide up and down. At the start of a test, the robot was suspended by an elastic band. A movement detector measured how much lift, if any, the robot produced for any given movement. A computer program fed the robot random instructions, at the rate of 20 per second, to test its flapping abilities. Each instruction told the robot either to do nothing or to move the wings slightly in the various directions. Feedback from the movement detector let the program work out which sets of instructions were best at producing lift. The most successful ones were paired up and "offspring" sets of instructions were generated by swapping instructions randomly between successful pairs. These next-generation instructions were then sent to the robot and evaluated before breeding a new generation, and the process was repeated.

单选题She all but fainted when she heard the news.

单选题Take vigorous exercise for several hours a week.

单选题Light Night, Dark Stars Thousands of people around the globe step outside to gaze at their night sky. On a clear night, with no clouds, moonlight, or artificial lights to block the view, people can see more than 14,000 stars in the sky, says Dennis Ward, an astronomer with the University Corporation for Atmospheric Research (UCAR) in Boulder, Colo. But when people are surrounded by city lights, he says, they're lucky to see 150 stars. If you've ever driven toward a big city at night and seen its glow from a great distance, you've witnessed light pollution. It occurs when light from streetlights, office buildings, signs, and other sources streams into space and illuminates the night sky. This haze of light makes many stars invisible to people on Earth. Even at night, big cities like New York glow from light pollution, making stargazing difficult. Dust and particles of pollution from factories and industries worsen the effects of light pollution. "If one city has a lot more light pollution than another," Ward says, "that city will suffer the effects of light pollution on a much greater scale." Hazy skies also make it far more difficult for astronomers to do their jobs. Cities are getting larger. Suburbs are growing in once dark, rural areas. Light from all this new development is increasingly obscuring the faint light given off by distant stars. And if scientists can't locate these objects, they can't learn more about them. Light pollution doesn't only affect star visibility. It can harm wildlife too. It's clear that artificial light can attract animals, making them go off course. There's increasing evidence, for example, that migrating birds use sunsets and sunrises to help find their way, says Sydney Gauthreaux Jr., a scientist at Clemson University in South Carolina "When light occurs at night," he says, "it has a very disruptive influence." Sometimes birds fly into lighted towers, high-rises, and cables from radio and television towers. Experts estimate that millions of birds die this way every year.