单选题The view from my bedroom window was absolutely spectacular. A. general B. traditional C. magnificent D. strong

单选题I catch cold now and then .

单选题A small increase in the earth's temperature may bring about

单选题 Hair Detectives Scientists have found a way to use hair to figure out where a person is from and where that person has been. The finding could help solve crimes, among other useful applications. Water is central to the new technique. Our bodies break water down into its parts: hydrogen (氢) and oxygen. Atoms (原子) of these two elements end up in our tissues and hair. But not all water is the same. Hydrogen and oxygen atoms can vary in how much they weigh. Different forms of a single element are called isotopes (同位素). And depending on where you live, tap water contains unique proportions of the heavier and lighter isotopes of hydrogen and oxygen. Might hair record these watery quirks (古怪举动；怪癖)? That's what James R. Ehleringer, an environmental scientist at the University of Utah in Salt Lake City, wondered. To find out, he and his colleagues collected hair from barbers and hair stylists (发型师) in 65 cities in 18 states across the United States. The researchers assumed that the hair they collected came from people who lived in the area. Even though people drink a lot of bottled water these days, the scientists found that hair overwhelmingly (压倒性的) reflected the concentrations of hydrogen and oxygen isotopes in local tap water. That's probably because people usually cook their food in the local water. What's more, most of the other liquids people drink including milk and soft drinks contain large amounts of water that also come from sources within their region. Scientists already knew how the composition of water varies throughout the country. Ehleringer and colleagues combined that information with their results to predict the composition of hair in people from different regions. One hair sample used in Ehleringer's study came from a man who had recently moved from Beijing, China, to Salt Lake City. As his hair grew, it reflected his change in location. The new technique can't point to exactly where a person is from, because similar types of water appear in different regions that span a broad area. But authorities can now use the information to analyze hair samples from criminals or crime victims and narrow their search for clues (线索).

单选题This report Uconcerns/U a man who lives in London, but works in Paris.

单选题The steadily rising cost of labor on the waterfront has greatly increased the cost of shipping cargo by water.

单选题The North American desert, a vast belt of inhospitable terrain, stretches {{U}}erratically{{/U}} down the western side of the continent.

单选题The world champion suffered a sensational defeat.

单选题A local hypnotist (催眠师) offered his services, and Edgar readily accepted.

单选题It is laid down in the regulations that all members must carry their membership cards at all times.

单选题Unfortunately, the rate of his expenditure surpasses that of his income.

单选题General acceptance of 3-D films may prove hard to come by.A. obtainB. explainC. understandD. distinguish

单选题A．small number of firms have ceased trading. A．completed B．finished C．fulfilled D．stopped

单选题Can you give me a concrete example to support your idea?

单选题She can speak French and German, let alone English.A. to say nothing ofB. to speak nothing ofC. to talk nothing ofD. to tell nothing of

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Microchip Research Center Created A research center has been 1 in this Far Eastern country to develop advanced microchip production technology. The center, which will start out with about US $14 million, will help the country develop its chip industry without always depending on imported technology. The center will make use of its research skills and 2 to develop new technology for 3 chip plants. The advent of the center will possibly free the country from the 4 that it is always buying almost-outdated technologies from other countries, said the country"s flagship chipmaker. 5 , chip plants in this country are in a passive situation because many foreign governments don"! allow them to 6 the most advanced technologies, fearing they will be used for 7 purposes. Moreover, the high licensing fees they have to pay to technology providers are also an important 8 for their decision of self-reliance. As mainstream chip production technology 9 from one generation to the next every three to five years, plants with new technology can make more powerful chips at lower costs, while plants with 10 equipment, which often cost billions of dollars to build, will be 11 by the maker. More than 10 chip plants are being built, each costing millions of US dollars. The majority of that money goes to overseas equipment 12 and technology owners—mainly 13 Japan and Singapore. Should the new center play a major role m improving the situation in the industry, the country admits the US $14 million investment is still rather small. This country is developing 14 technologies. Most of the investment will be spent on setting 15 with technology and intellectual property owners.

单选题I am going as a {{U}}favor{{/U}} to Ann because I have to.

单选题We learn from the passage that the London & Blackwell railway

单选题They agreed to settle the dispute by peaceful means.