单选题She had a natural courtesy combined with unshakable conviction .

单选题"Salty" Rice Plant Boosts Harvests British scientists are breeding a new generation of rice plants that will be able to grow in soil containing salt water. Their work may enable abandoned farms to become productive once more. Tim Flowers and Tony Yeo, from Sussex University"s School of Biological Sciences, have spent several years researching how crops, such as rice, could be made to grow in water that has become salty. The pair has recently begun a three-year programme, funded by the Biotechnology and Biological Sciences Research Council, to establish which genes enable some plants to survive salty conditions. The aim is to breed this capability into crops, starting with rice. It is estimated that each year more than 10 million hectares (公顷) of agricultural land are lost because salt gets into the soil and stunts (妨碍生长) plants. The problem is caused by several factors. In the tropics, mangroves (红树木) that create swamps (沼泽) and traditionally formed barriers to sea water have been cut down. In the Mediterranean, a series of droughts have caused the water table to drop, allowing sea water to seep (渗透) in. In Latin America, irrigation often causes problems when water is evaporated (蒸发) by the heat, leaving salt deposits behind. Excess salt then enters the plants and prevents them functioning normally. Heavy concentrations of minerals in the plants stop them drawing up the water they need to survive. To overcome these problems, Flowers and Yeo decided to breed rice plants that take in very little salt and store what they do absorb in cells that do not affect the plants" growth. They have started to breed these characteristics into a new rice crop, but it will take about eight harvests before the resulting seeds are ready to be considered for commercial use. Once the characteristics for surviving salty soil are known, Flowers and Yeo will try to breed the appropriate genes into all manners of crops and plants. Land that has been abandoned to nature will then be able to bloom again, providing much needed food in the poorer countries of the world.

单选题The very north and south regions are covered with ice and snow. A. areas B. rocks C. mountains D. districts

单选题For urban areas this approach was wholly inadequate. A．really B．basically C．fundamentally D．completely

单选题On Thanksgiving in the United States, families gather and give thanks for the blessing of the past year.A. pick upB. come togetherC. competeD. correspond

单选题The word "diversity" in the last paragraph means

单选题He could not {{U}}tolerate{{/U}} the extremes of heat in the desert. A.bear B.hate C.like D.criticize

单选题We learn from the passage that the writer

单选题Grounded whales often struggle fruitlessly to reenter deep water.

单选题{{B}}第二篇{{/B}} {{B}}A Sunshade for the Planet{{/B}} Even with the best will in the world, reducing our carbon emissions is not going to prevent global warming. It has become clear that even if we take the most strong measures to control emissions, the uncertainties in our climate models still leave open the possibility of extreme warming and rises in sea level. At the same time, resistance by governments and special interest groups makes it quite possible that the actions suggested by climate scientists might not be implemented soon enough. Fortunately, if the worst comes to the worst, scientists still have a few tricks up their sleeves. For the most part they have strongly resisted discussing these options for fear of inviting a sense of complacency that might thwart efforts to tackle the root of the problem. Until now, that is. A growing number of researchers are taking a fresh look at large-scale "geoengineering" projects that might be used to counteract global warming. "I use the analogy of methadone," says Stephen Schneider, a climate researcher at Stanford University in California who was among the first to draw attention to global warming. "If you have a heroin addict, the correct treatment is hospitalization, and a long rehab. But if they absolutely refuse, methadone is better than heroin." Basically the idea is to apply "sunscreen" to the whole planet. One astronomer has come up with a radical plan to cool Earth: launch trillions of feather-light discs into space, where they would form a vast cloud that would block the sun's rays. It's controversial, but recent studies suggest there are ways to deflect just enough of the sunlight reaching the Earth's surface to counteract the warming produced by the greenhouse effect. Global climate models show that blocking just 1.8 per cent of the incident energy in the sun's rays would cancel out the warming effects produced by a doubling of greenhouse gases in the atmosphere. That could be crucial, because even the most severe emissions-control measures being proposed would leave us with a doubling of carbon dioxide by the end of this century, and that would last for at 1east a century more.

单选题His answers were obscure and confusing.

单选题Kit Carson, an American frontiersman, was one of the most sensational heroes of the Old West.

单选题Saving Money Where you save your money often depends on what you are saving for. If you are saving to buy a CD．(光盘) or to go to a concert, then probably you would keep your money somewhere in your room. If you are saving for a big purchase like a mountain bike or a school trip, where would you save your money? One place to save money is the bank. Putting your money in a savings account will help your money earn more money. If you put your money in a piggy bank (猪形储蓄罐), one year later you'll still have the same amount of money you put in. If you put your money in a savings account, one year later, you'll have more money than you put in. Why? When you keep your money in a bank, your money earns interest. Interest is an amount of money a bank pays you to use your money. The bank uses your money (and the money of other people, too) to loan money to people and businesses. The bank will send you a statement several times a year. A．bank statement tells you how much money you have in your account. It also tells you how much interest you have earned. If you leave your money in the bank, you can watch it grow! Another way you can save money is to buy a certificate of deposit or CD. If you have some money that you don't need to use for a long time, this is a good way to make your money grow. You can buy a CD．at a bank. You agree not to use the money for a certain period of time. That period might be from six months to five years. You can't touch your money during that time. If you do, you must pay a penalty, or fee.

单选题Did anyone {{U}}call{{/U}} me when I was out? A. invite B. name C. answer D. phone

单选题Man cannot exist without water.

单选题Long Bus Ride Long bus rides are like television shows. They have a beginning, a middle, and an end—with commercials thrown in every three or four minutes. The commercials are unavoidable. They happen whether you want them or not. Every couple of minutes a billboard (广告牌) glides by outside the bus window. "Buy Super Clean Toothpaste." "Drink Good"n Wet Root Beer." "Fill up with Pacific Gas." Only if you sleep, which is equal to turning the television set off, are you spared the unending cry of "You Need It! Buy It Now!" The beginning of the ride is comfortable and somewhat exciting, even if you"ve traveled that way before. Usually some things have changed—new houses, new buildings, sometimes even a new road. The bus driver has a style of driving and it"s fun to try to figure it out the first hour or so. If the driver is particularly reckless(鲁莽的) or daring, the ride can be as thrilling as a suspense story. Will the driver pass the truck in time? Will the driver move into the right or the left-hand lane? After a while, of course, the excitement dies down. Sleeping for a while helps pass the middle hours of the ride. Food always makes bus rides more interesting. But you"ve got to be careful of what kind of food you eat. Too much salty food can make you very thirsty between stops. The end of the ride is somewhat like the beginning. You know it will soon be over and there"s a kind of expectation and excitement in that. The seat, of course, has become harder as the hours have passed. By now you"ve sat with your legs crossed, with your hands crossed behind your head. The end comes just at the right time. There are just no more ways to sit.

单选题Human Ingenuity Since the dawn of human ingenuity, people have devised ever more cunning tools to cope with work that is dangerous, boring, burdensome, or just plain nasty. That compulsion has resulted in robotics—the science of conferring various human capabilities on machines. And if scientists have yet to create the mechanical version of science fiction, they have begun to come close. As a result, the modern world is increasingly populated by intelligent gizmos whose presence we barely notice but whose universal existence has removed much human labor. Our factories hum to the rhythm of robot assembly arms. Our banking is done at automated teller terminals that thank us with mechanical politeness for the transaction. Our subway trains are controlled by tireless robo-drivers. And thanks to the continual miniaturization of electronics and micro-mechanics, there are already robot systems that can perform some kinds of brain and bone surgery with submillimeter accuracy—far greater precision that highly skilled physicians can achieve with their hands alone. But if robots are to reach the next stage of laborsaving utility, they will have to operate with less human supervision and be able to make at least a few decisions for themselves—goals that pose a real challenge. "While we know how to tell a robot to handle a specific error, "says Dave Lavery, manager of a robotics program at NASA, "we can't yet give a robot enough 'common sense' to reliably interact with a dynamic world. " Indeed the quest for true artificial intelligence has produced very mixed results. Despite a spell of initial optimism in the 1960s and 1970s when it appeared that transistor circuits and microprocessors might be able to copy the action of the human brain by the year 2010, researchers lately have begun to extend that forecast by decades if not centuries. What they found, in attempting to model thought, is that the human brain's roughly one hundred billion nerve cells are much more talented—and human perception far more complicated-than previously imagined. They have built robots that can recognize the error of a machine panel by a fraction of a millimeter in a controlled factory environment. But the human mind can glimpse a rapidly changing scene and immediately disregard the 98 percent that is irrelevant, instantaneously focusing on the monkey at the side of winding forest road or the single suspicious face in a big crowd. The most advanced computer systems on Earth can't approach that kind of ability, and neuroscientists still don't know quite how we do it.

单选题There is an abundant supply of cheap labor in this country.

单选题Seeing Red Means Danger Ahead The color red often means danger and by paying attention, accidents can be prevented. In the future, the color red also may help (51) danger at construction sites. Thanks to new work by engineers, bridge supports or (52) kinds of materials could one day contain a color switching material. It will turn red (53) a structure collapses or falls apart. The secret (54) the color switching material is a particular type of molecule. A molecule is a group of atoms held together by chemical bonds. Molecules come (55) all shapes and sizes, and make up (56) . You can see, touch Or feel. How a molecule behaves depends on (57) kinds of atoms it contains, and how they're held together. When a polymer (聚合物) containing a color switching molecule called a mechanophore (机械响应性聚合物) which is about to break, it produce a (58) When a polymer with mechanophore molecules becomes "injured" or (59) , one of the mechanophore bonds (60) and the material turns red. "It's a really simple detection method." says Nancy Sottos, one of the scientists who worked on the project. Sottos and her team tested the color switching polymers in their lab. The test (61) proved encouraging. There is a way to get rid of the color light when a bright light is shone on the mechanophore. The broken bond is fixed and the red color (62) . This "self-healing" may be a problem for engineers. They need to use the color changer in big construction projects that will be (63) in sunlight. And sunlight will make the mechanophore's warming system (64) . Sottos and her fellow scientists still have (65) work to do before the color switching molecules can be used outside the lab.

单选题The passage is mainly about features and implications of the new era.