单选题Susan never took any cookery courses; she learned cooking by ______ useful tips from TV cookery programs.

单选题John did not have to write the composition if he didn't want to. It was ______.

单选题{{B}}Passage 1{{/B}} Gene therapy and gene-based drugs are two ways we could benefit from our growing mastery of genetic science. But there will be others as well. Here is one of the remarkable therapies on the cutting edge of genetic research that could make their way into mainstream medicine in the coming years. While it's true that just about every cell in the body has the instructions to make a complete human, most of those instructions are inactivated, and with good reason: the last thing you want for your brain cells is to start churning out stomach acid or your nose to turn into a kidney. The only time cells truly have the potential to turn into any and all body parts is very early in a pregnancy, when so-called stem cells haven't begun to specialize. Yet this untapped potential could be a terrific boon to medicine. Most diseases involve the death of healthy cells-brain cells in Alzheimer's, cardiac cells in heart disease, pancreatic cells in diabetes, to name a few. If doctors could isolate stem cells, then direct their growth, they might be able to furnish patients with healthy replacement tissue. It was incredibly difficult, but last fall scientists at the University of Wisconsin managed to isolate stem ceils and get them to grow into neural, gut, muscle and bone cells. The process still can't be controlled, and may have unforeseen limitations; but if efforts to understand and master stem-cell development prove successful, doctors will have a therapeutic tool of incredible power. The same applies to cloning, which is really just the other side of the coin; true cloning, as first shown with the sheep Dolly two years ago, involves taking a developed cell and reactivating the genome within, resetting its developmental instructions to a pristine state. Once that happens, the rejuvenated cell can develop into a full-fledged animal, genetically identical to its parent. For agriculture, in which purely physical characteristics like milk production in a cow or low fat in a hog have real market value, biological carbon copies could become routine within a few years. This past year scientists have done for mice and cows what Ian Wilmut did for Dolly, and other creatures are bound to join the cloned menagerie in the coming year. Human cloning, on the other hand, may be technically feasible but legally and emotionally more difficult. Still, one day it will happen. The ability to reset body cells to a pristine, undeveloped state could give doctors exactly the same advantages they would get from stem cells., the potential to make healthy body tissues of all sorts, and thus to cure disease. That could prove to be a true "miracle cure."

单选题 Water is the oldest form of transport. The original sailing vessels were replaced by steamboats in the early 1800s and by diesel power in the 1920s. A distinction is generally made between deepwater and navigable inland water transport. Domestic commerce centers on tile Great Lakes, canals, and navigable rivers. In 1975 water transport accounted for 22.6 percent of total intercity tonnage. Its relative share of intercity tonnage was 31.3 percent in 1947 and 31.7 percent in 1958. Tonnage declined to 27.9 percent in 1965 but increased by 1970 to 28.4 percent. This short-term increase did not stabilize. Market share dropped by 5.8 percent by 1975. Forecasted market share by 1985 is 18.4 percent of total intercity tonnage. The water transport share of revenue has been less than 2 percent of intercity freight revenue since 1955. The exact miles of improved waterways in operation depend in part on whether coastwise and intercostal shipping are included. Approximately 26,000 miles of improved inland waterways were operated in 1975. Fewer miles of improved inland waterways exist than of any other transportation mode. The main advantage of water transport is the capacity to move extremely large shipments. Deepwater vessels are restricted in operation, but diesel-towed barges have a fair degree of flexibility. In comparison to rail and highway, water transport ranks in the middle with respect to fixed cost. The fixed cost of operation is greater than that of motor carriers but less than that of railroads. The main disadvantage of water is the limited degree of flexibility and the low speeds of transport. Unless the source and destination of the movement are adjacent to a waterway, supplemental haul by rail or truck is required. The capability of water to transport large tonnage at low variable cost places this mode of transport in demand when low freight rates are desired and speed of transit is a secondary consideration. Freight transported by inland water leans heavily to mining and basic bulk commodities, such as chemicals, cement, and selected agricultural products. In addition to the restrictions of navigable waterways, terminal facilities for bulk arid dry cargo storage and load-unload devices limit the flexibility of water transport. Labor restrictions on loading and unloading at dock level create operational problems and tend to reduce the potential range of available traffic. Finally, a highly competitive situation has developed between railroads and inland water carriers in areas where parallel routings exist. Inland and Great Lakes water transport will continue to be a viable alternative for future logistical system design. The full potential of the St. Lawrence Seaway has not yet been realized with respect to domestic freight. The slow passage of inland river transport can provide a form of warehousing in transit if fully integrated into overall system design. Improvements in ice-breaking equipment appear on the verge of eliminating the seasonal limitations of water transport.

单选题Prince Charles, the longest-waiting ______ to the throne in British history, has spoken of his "impatience" to get things done.

单选题She got very angry and ______ her clothes about in the room.

单选题In the meantime, the question facing business is whether such research is ______ the costs. A. worth B. worth of C. worthy D. worthwhile

单选题The trucks______ heavy goods from factories to the ports.(2004年上海理工大学考博试题)

单选题The pronoun "They" (Line 1, Para. 4) refers to ______.

单选题The advertising industry has resorted to self-regulation in a serious effort to curtail not only bad taste but also misrepresentation and deception in copy and illustrations.

单选题Offshore exploration below the shallow waters of the Persian Gulf has revealed the ______ of large resources of oil and gas. [A] attendance [B] presence [C] inhabitant [D] presentation

单选题President Clinton______power when the US economy was slow.(2004年西南财经大学考博试题)

单选题The teacher wrote a brief comment in the ______ to show the student why it was wrong. A.manual B.margin C.edge D.verge

单选题Not until Kentucky's Mammoth Cave had been completely explored in 1972______.

单选题The El Nino ("little boy" in Spanish) that pounded the globe between the summers of 1997 and 1998 was in some measure the most destructive in this century. Worldwide damage estimates exceed ￡ 20 billion--not to mention the human death toll caused by resulting droughts, floods and bushfires. El Nino and La Nina ( "little girl" ) are part of a seesawing of winds and currents in the equatorial Pacific called ENSO ( El Nino Southern Oscillation) that appears every two to eight years. Normally, westward-blowing trade winds caused by the rotation of the earth and conditions in the Tropics push surface water across the Pacific towards Asia. The warm water piles up along the coasts of Indonesia, Australia and the Philippines, raising sea levels more than a foot above those on the South American side of the Pacific. As El Nino builds the normal east-to-west trade winds wane. Like water splashing in a giant bathtub, the elevated pool of warm water washes from Asian shores back towards South America. In last season' s cycle, surface temperatures off the west coast of South America soared from a normal high of 23℃ degrees to 28℃ degrees. This area of warm water, twice the size of the continental US, interacted with the atmosphere, creating storms and displacing high-altitude winds. El Nino brought rain that flooded normally dry coastal areas of Ecuador, Chile and Peru, while droughts struck Australia and Indonesia. Fires destroyed some five million acres of Indonesian for est. The drought, along with the economic crisis, left about five million people desperate for food and water. These conditions helped set the stage for riots that led to the downfall of President Suharto. El Nino also took the blame for extreme temperatures in Texas last summer--over 38℃ degrees for a record 30 days in a row. In Florida, lush vegetation turned to tinder and bushfires raged. Even Britain has been sweltering with our hottest year on record in 1997.

单选题The______ of electrical energy into thermal energy is a process that is easily carried out at 100% efficiency.(2006年中国矿业大学考博试题)