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Colors There are two ways to create colors in a photograph. One method, called additive, starts with three basis colors and adds them together to produce some other colors. The second method, called subtractive, starts with white light (a mixture of all colors in the spectrum) and, by taking away some or all other colors, leaves the one desired. In the additive method, separate colored lights combine to produce various other colors. The three additive primary colors are green, red and blue (each providing about one-third of the wavelengths in the total spectrum). Mixed in varying proportions, they can produce all colors. Green and red light mix to produce yellow; red and blue light mix to produce magenta; green and blue mix to produce cyan. When equal parts of all three of these primary-colored beams of light overlap, the mixture appears white to the eye. In the subtractive process, colors are produced when dye (as in paint or color photographic materials) absorbs some wavelengths and so passes on only part of the spectrum. The subtractive primaries are cyan (a bluish green), magents (a purplish pink), and yellow; these are the pigments or dyes that absorb red, green and blue wavelengths, respectively, thus subtracting them form white light. These dye colors are the complementary colors to the three additive primaries of red, green and blue. Properly combined the subtractive primaries and absorb all colors of light, producing black. But, mixed in varying proportions, they too can produce any color in the spectrum. Whether a particular color is obtained by adding colored lights together or by subtracting some light from the total spectrum, the result looks the same to the eye. The additive process was employed for early color photography. But the subtractive method, while requiring complex chemical techniques, has turned out to be more practical and is the basis of all modern color films. What does the passage mainly discuss
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阅读下面的短文，文中有15处空白，每处空白给出4个选项。请根据短文的内容，从4个选项中选择1个最佳答案。Reading Reading involves looking at graphic symbols and formulating mentally the sounds and ideas they represent. Concepts of reading have changed substantially over the centuries. During the 1950’s, and 1960’s especially, increased attention has been devote (51) defining and describing the reading process. (52) specialists agree that reading (53) a complex organization of higher mental (54) , they disagree (55) the exact nature of the process. Some experts, who regard language primarily as a code using symbols to represent sounds, (56) reading as simply the decoding of symbols into the sounds they stand (57) . These authorities (58) that meaning, being concerned with thinking, must be taught independently of the decoding process. Others maintain that reading is inextricably related to thinking, and that a child who pronounces sounds without (59) their meaning is not truly reading. The reader, (60) some, is not just a person with a theoretical ability to read but one who (61) reads. Many adults, although they have the ability to read have never read a book in its entirety. By some experts they would not be (62) as readers. Clearly, the philosophy, objectives, methods and materials of reading will depend on the definition one uses. By the most inclusive and satisfactory definition, reading is the ability to (63) the sound-symbol code of the language, to interpret meaning for various purposes, at various rates, and at various levels of difficulty, and to do (64) widely and enthusiastically. (65) , reading is the interpretation of ideas through the use of symbols representing sounds and ideas.
阅读下面这篇短文，短文后列出7个句子，请根据短文的内容对每个句子做出判断。Basic Research Vs. Applied Research Why does the Foundation concentrate its support on basic rather than applied research Basic research is the very heart of science, and its cumulative product is the capital of scientific progress, a capital that must be constantly increased as the demands upon its rise. The goal of basic research is understanding for its own sake. Understanding of the structure of the atom or the nerve cell, the explosion of a spiral nebula (螺旋星) or the distribution of cosmic dust, the causes of earthquakes and droughts, or of man as a behaving creature and of the social forces that are created whenever two of more human beings come into contact with one another—the scope is staggering, but the commitment to truth is the same. If the commitment were to a particular result, conflicting evidence might be overlooked or, with the best will in the world, simply not appreciated. Moreover, the practical applications of basic research frequently cannot be anticipated. When Roentgen, the physicist, discovered X-rays, he had no idea of their usefulness to medicine. Applied research, undertaken to solve specific practical problems, has an immediate attractiveness because the results can be seen and enjoyed. For practical reasons, the sums spent on applied research in any country always far exceed those for basic research, and the proportions are more unequal in the less developed countries. Leaving aside the funds devoted to research by industry—which is naturally far more concerned with applied aspects because these profits quickly—the funds the U.S. Government allots to basic research currently amount to about seven percent of its overall research and developments funds. Unless adequate safeguards are provided, applied research invariably tends to drive out basic. Then, so Dr. Waterman has pointed out, development will inevitably be undertaken prematurely(过早的), career incentives will gravitate strongly toward applied science, and the opportunities for making major scientific discoveries will be lost. Unfortunately, pressures to emphasize new developments, without corresponding emphasis upon pure science. Tend to degrade the quality of the nation’s technology in the long run, rather than to improve it. The United States Government currently concentrates its support on applied rather than on basic research.
阅读下面这篇短文，短文后列出7个句子，请根据短文的内容对每个句子做出判断。Basic Research Vs. Applied Research Why does the Foundation concentrate its support on basic rather than applied research Basic research is the very heart of science, and its cumulative product is the capital of scientific progress, a capital that must be constantly increased as the demands upon its rise. The goal of basic research is understanding for its own sake. Understanding of the structure of the atom or the nerve cell, the explosion of a spiral nebula (螺旋星) or the distribution of cosmic dust, the causes of earthquakes and droughts, or of man as a behaving creature and of the social forces that are created whenever two of more human beings come into contact with one another—the scope is staggering, but the commitment to truth is the same. If the commitment were to a particular result, conflicting evidence might be overlooked or, with the best will in the world, simply not appreciated. Moreover, the practical applications of basic research frequently cannot be anticipated. When Roentgen, the physicist, discovered X-rays, he had no idea of their usefulness to medicine. Applied research, undertaken to solve specific practical problems, has an immediate attractiveness because the results can be seen and enjoyed. For practical reasons, the sums spent on applied research in any country always far exceed those for basic research, and the proportions are more unequal in the less developed countries. Leaving aside the funds devoted to research by industry—which is naturally far more concerned with applied aspects because these profits quickly—the funds the U.S. Government allots to basic research currently amount to about seven percent of its overall research and developments funds. Unless adequate safeguards are provided, applied research invariably tends to drive out basic. Then, so Dr. Waterman has pointed out, development will inevitably be undertaken prematurely(过早的), career incentives will gravitate strongly toward applied science, and the opportunities for making major scientific discoveries will be lost. Unfortunately, pressures to emphasize new developments, without corresponding emphasis upon pure science. Tend to degrade the quality of the nation’s technology in the long run, rather than to improve it. X-rays used in medical researches belong to the scope of basic research.
患者男性，43岁，以上腹间歇性疼痛和腹泻1年来诊。查体：腹软，上腹压痛，无反跳痛及肌紧张。 MRCP：慢性胰腺炎。 患者可能有的临床表现为
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