单选题China does a lot of trade with many countries.

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 have 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 10m 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 (绿树林) 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 but 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They are endeavoring to change society as a whole.A. tryingB. workingC. doingD. making

单选题She answered the difficult question, which was an immense load off her heart. A. natural B. fatal C. tiny D. enormous

单选题Transportation For many years in the desert, camels used to be the only form of transportation (运输). Before the age of modern trains, camel trains were used to carry all the goods for trading between Central Africa and Europe. Traders sometimes put together camel trains with 10,000 to 15,000 animals. Each animal often carried as much as 400 pounds and could travel twenty miles a day. This form of transportation used to be so important that camels were called "ships of the desert". Now modem trains travel across the desert in a very short time. One engine can pull as much weight as 135,000 camels. In addition, trains use special cars (车厢) for their load. Refrigerator cars carry food; boxcars (棚车) carry heavy goods; stock cars carry animals; and tank cars carry oil. Air travel is also a modem means of transportation, but it has changed since the early 20th century. The earliest planes were biplanes (双翼飞机), with two sets of wings. The top speed of this plane was 60 miles per hour. The pilots used to sit or lie on the wings in the open air. The plane engines sometimes stopped in the middle of a trip. It used to be impossible to fly in bad weather. In snow or in rain, the wings frequently became icy. Then the plane might go down. Mechanical improvements during the First World War changed airplanes. Monoplanes (单翼飞机) took the place of biplanes. Pilots flew inside of covered cabins. Still, even these planes were small and expensive. Only rich people used to be able to travel in airplanes. Now modem jets make air travel possible for all people. No place in the world is more than 24 hours away by jet. Further improvements have lowered the cost of flying, and they have made air travel much safer than it used to be. A modern 707 can carry 170 people and can fly at 600 miles per hour. People never used to eat, sleep, or watch movies on airplanes. Now these things are a normal part of air travel.

单选题The Foreign Service is a {{U}}branch{{/U}} of the Department of State．

单选题That player is etemally arguing with the refereeA. desperatelyB. constantlyC. eventuallyD. extensively

单选题Would you please Ucall/U my husband aS soon as possible?

单选题To solve the problem of dry mouths, one is advised to take cool milk.

单选题Oil and Economy Could the bad old days of economic decline be about to return? Since OPEC agreed to supply-cuts in March, the price of crude oil has jumped to almost $ 26 a barrel, up from less than $10 last December. This near-tripling of oil prices calls up scary memories of the 1973 oil shock, when prices quadrupled, and 1979—1980, when they also almost tripled. Both previous shocks resulted in double-digit inflation and global economic decline. So where are the headlines warning of gloom and doom this time? The oil price was given another push up this week when Iraq suspended oil exports. Strengthening economic growth, at the same time as winter grips the northern hemisphere, could push the price higher still in the short term. Yet there are good reasons to expect the economic consequences now to be less severe than in the 1970s. In most countries the cost of crude oil now accounts for a smaller share of the price of petrol than it did in the 1970s. In Europe, taxes account for up to four-fifths of the retail price, so even quite big changes in the price of crude have a more muted effect on pump prices than in the past. Rich economies are also less dependent on oil than they were, and so less sensitive to swings in the oil price. Energy conservation, a shift to other fuels and a decline in the importance of heavy, energy-intensive industries have reduced oil consumption. Software, consultancy and mobile telephones use far less oil than steel or car production. For each dollar of GDP (inconstant prices) rich economies now use nearly 50% less oil than in 1973. The OECD estimates in its latest Economic Outlook that, if oil prices averaged $22 a barrel for a full year, compared with $13 in 1998, this would increase the oil import bill in rich economies by only 0.25-0.5% of GDP. That is less than one-quarter of the income loss in 1974 or 1980. On the other hand, oil-importing emerging economies-to which heavy industry has shifted-have become more energy-intensive, and so could be more seriously squeezed. One more reason not to lose sleep over the rise in oil prices is that, unlike the rises in the 1970s, it has not occurred against the background of general commodity-price inflation and global excess demand. A sizable portion of the world is only just emerging from economic decline. The Economist's commodity price index is broadly unchanging from a year ago. In 1973 commodity prices jumped by 70%, and in 1979 by almost 30%.

单选题Some People Do Not Taste Salt like Others Low-salt foods may be harder for some people to like than others, according, to a study by a Penn State College of Agricultural Sciences food scientist. The research indicates that genetic factors influence some of the difference in the levels of salt we like to eat. Those conclusions are important because recent, well-publicized (大力宣传的) efforts to reduce the salt content in food have left many people struggling to accept food that simply does not taste as good to them as it does to others, pointed out John Hayes, lead investigator on the study. Diets high in salt can increase the risk of high blood pressure and stroke. That is why public health experts and food companies are working together on ways to help consumers lower salt intake through foods that are enjoyable to eat. This study increases understanding of salt preference and consumption. The research involved 87 carefully screened participants who sampled salty foods such as soup and chips, on multiple occasions, spread out over weeks. Test subjects were 45 men and 42 women, reportedly healthy, ranging in age from 20 to 40. They rated the intensity of taste on a commonly used scientific scale, ranging from barely detectable to strongest sensation of any kind. "Most of us like the taste of salt. However, some individuals eat more salt, both because they like the taste of saltiness more, and also because it is needed to block other unpleasant tastes in food, " said Hayes. "Supertasters, people who experience tastes more intensely, consume more salt than nontasters. Snack foods have saltiness as their primary flavor, and at least for these foods, more is better, so the supertasters seem to like them more. " However, supertasters also need higher levels of salt to block unpleasant bitter tastes in foods such as cheese, Hayes noted. "For example, cheese is a wonderful blend of dairy flavors from fermented (发酵地) milk, but also bitter tastes from ripening that are blocked by salt, " he said. "A supertaster finds low-salt cheese unpleasant because the bitterness is too pronounced. " Hayes cited research done more than 75 years ago by a chemist named Fox and a geneticist named Blakeslee, showing that individuals differ in their ability to taste certain chemicals. As a result, Hayes explained, we know that a wide range in taste acuity(敏锐) exists, and this variation is as normal as variations in eye and hair color.

单选题When the tree falls, the monkeys scatter .

单选题When does the next train {{U}}depart{{/U}}? A.pull up B.pull down C.pull out D.pull in

单选题下面有3篇短文，每篇短文后有5道题，每题后面有4个选项。请仔细阅读短文并根据短文回答其后面的问题，从4个选项中选择1个最佳答案。 {{B}}第一篇{{/B}} One of the greatest mysteries of the world, for 'which scientist have so far been unable to find any satisfactory explanation, is the Bermuda Triangle, sometime called "the Graveyard of the Atlantic." This is an area of the western Atlantic between Bermuda and Florida, roughly triangular in shape where since 1945 at least a hundred ships and planes and over a thousand people have disappeared. No wreckage had been found, no bodies, lifebelts or any other evidence of disater. It is as if these planes, ships and people had never existed. In some cases a routine radio message has been received from aircraft reporting everything in order a few minutes before all contact was lost, in others a weak S. O. S message has been picked up and, in perfect weather, inexplicable references to fog and loss of bearings. In the extraordinary case of five U. $. navy planes disappearing on a routine mission from Florida, the rescue place sent to locate them vanished also. There have been references to the curious white light or haze which is a feature of the sea in part of this area, and it is interesting to note that not only was this light, or streaks of light, observed by the astronauts on their way to space, but was also noted by Columbus, five centuries ago. Whether this light has any connection with the mysterious disappearance is unknown-it is just another curious circumstance as yet unexplained. Many theories, some bordering on the fantastic, have been advanced to account for the disturbing incidents that occur in the area of the Bermuda Triangle. It has been asked whether these disappearances are caused by extraterrestrial activity, by some undiscovered source of energy, or some dimension of time or space unguessed at by Man. This is no answer and speculation continues as anxiety increases.

单选题Smoking is not permitted in the office. A. probable B. possible C. admitted D. allowed

单选题I'd very much like to know what your aim in life is； A．thought B．idea C．goal D．plan

单选题This hotel has established a very good {{U}}reputation{{/U}}.

单选题Many failures in communication ______ from mutual misunderstanding.A. approveB. raiseC. riseD. arise

单选题{{B}}第二篇{{/B}} A Historical Development of Oil Refining An important new industry, oil refining(炼油) ,grew after the Civil War. Crude oil, or petroleum-a dark, thick ooze from the earth-had been known for hundreds of years. But little use had ever been made of it. In the 1850's, Samuel M. Kier, a manufacturer in western Pennsylvania, began collecting the oil from local seepages (油苗)and refining it into kerosene (煤油), Refining, like smelting(锻造), is a process of removing impurities from a raw material. Kerosene was used to light lamps. It was a cheap substitute for whale oil, which was becoming harder to get. Soon there was a large demand for kerosene. People began to search for new supplies of petroleum. The first oil well was drilled by E. L. Drake, a retired railroad conductor. In 1859 he began drilling in Titusville, Pennsylvania. The whole venture seemed so impractical and foolish that onlookers called it" Drake's Folly". But when he had drilled down about 70 feet(21 meters) ,Drake struck oil; his well began to yield 20 barrels of crude oil a day. News of Drake's success brought oil prospectors (探寻者)to the scene. By the early 1860s these wildcatters (盲目采油者) were drilling for "black gold" all over western Pennsylvania. The boom rivaled the California gold rush of 1848 in its excitement and Wild West atmosphere. And it brought far more wealth to the prospectors than any gold rush. Crude oil could be refined into many products. For some years kerosene continued to be the principal one, it was sold in grocery stores and door to door. In the 1880s and 1890s refiners learned how to make other petroleum (石油) products such as waxes (石蜡) and lubricating oils (润滑油). Petroleum was not then used to make gasoline or heating oil.

单选题Please give my best wishes to your family.