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Passage ThreeQuestions 32 to 35 are based on the passage you have just heard.
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Passage TwoQuestions 29 to 31 are based on the passage you have just heard.
[文档开始] 燥声的危害 燥声是任何一种人都不需要的声音，不论是音乐，还是机器发出来的声音，只要令人生厌，对人们形成干扰，它们就被称为燥声。一般将60分贝作为令人烦恼的音量界限，超过60分贝就会对人体产生种种危害。 强烈的燥声会引起听觉器官的损伤。当你刚从机器轰鸣的厂房出来时，可能会感到耳朵听不清声音了，必须过一会儿才能恢复正常，这便是燥声性耳聋。如果长期在这种环境下工作，会使听力显著下降。 燥声会严重干扰中枢神经正常功能，使人神经衰弱、消化不良，以至恶心、呕吐、头痛，它是现代文明病的一大根源。 燥声还会影响人们的正常工作和生活，使人不易入睡，容易惊醒，产生各种不愉快的感觉，对脑力劳动者和病人的影响就更大了。 [文档结束] 在考生文件夹下，打开文档WDA3_01.DOC，插入文档WTA3_01.DOC，将文中所有错词“燥声”替换为“噪声”。存储为文档WDA3_01.DOC。
TEXT A Science is a cumulative body of knowledge about the natural world, obtained by the application of a particular method practised by the scientist. The word science itself is derived from the Latin scire, which means to know, to have knowledge of or to experience. Technology is the fruit of applied science, it is the concrete expression of research done in the laboratory and applied to manufacturing commodities to meet human needs. The word scientist was introduced only in 1840 by William Whewell, Professor of Moral Philosophy at the University of Cambridge. In his Philosophy of the Inductive Sciences, he wrote: "We need a name to describe a cultivator of science in general. I should be inclined to call him a scientist." The "cultivators of science" before 1840 were known as "natural philosophers". The founders of the 300-year-old Royal Society were typical "natural philosophers". They were curious, often eccentric persons who poked inquiring fingers at nature. In the process of doing so they stated a technique of inquiry we know today as the "scientific method". Briefly, these are the steps in the method. First comes the thought that sparks off the inquiry. (For. example, in 1896, the physicist Henri Becquerel, in communications to the French Academy of Sciences, stated that he found that uranium salts emitted rays of unknown nature. His discovery excited Marie Curie. Along with her husband Pierre, she wanted to know more about this radiation. What was it exactly, and where did it come from) Second comes the collecting of facts: the techniques of doing this will differ according to the problem to be solved. However it is based on experiments in which one may use anything from a test tube to an earth satellite to gather essential data. (If you do not know the difficulties which the Curies encountered to gather their facts, as they investigated the mysterious uranium rays, I advise you to read the remarkable story in the book Madame Curie by her daughter Eve. ) This leads to step three: organising the facts and studying the relationships that emerge. (These rays were different from anything known. How can this be explained Did this radiation come from the atom itself It might well be that other materials also emit radiation. Madame Curie investigated and found this was so. She invented the word radioactivity for this phenomenon. She followed this with further experimental work on only "active" radioelements. ) Step four is the statement of a hypothesis or theory: that is, framing a general truth that has emerged and that may be modified as new facts emerge. (In July 1898, the Curies announced the probable presence in pitchblende ores of a new element endowed with powerful radioactivity. This was the beginning of the discovery of radium. ) Then follows the clearer statement of the theory. (In December 1898, the Curies reported to the Academy of Sciences: "The various reasons we have enumerated lead us to believe that the new radioactive substance contains a new element to which we propose to give the name of Radium. The new radioactive substance certainly contains a very strong proportion of bariums in spite of that its radioactivity is considerable. The radioactivity of radium therefore must be enormous. ") And the final step is the practical test of the theory--the prediction of new facts. This is essential because from this flows the possibility of control by man of the forces of nature that are newly revealed. Note how Marie Curie used deductive reasoning in order to push on. "This kind of detective work is basic to the methodology of science. Further, she was concerned with probability and not certainty-in her investigations. Also, although the Curies were doing the basic research work at great expense to themselves in hard physical toil, they knew that they were part of an international group of people all concerned with their search for truth. Their reports were published and immediately examined by scientists all over the world. Any flaws in their argument, would be pointed out to them immediately. Which of the following questions might the Curies NOT ask in their investigations
Rain forests Tropical rainforests are the most diverse ecosystem (生态系统) on Earth, and also the oldest. Today, tropical rainforests cover only 6 percent of the Earth’s ground surface, but they are home to over half of the planet’s plant and animal species.What Is a Rainforest Generally speaking, a rainforest is an environment that receives high rainfall and is dominated by tall trees. A wide range of ecosystems fall into this category, of course. But most of the time when people talk about rainforests, they mean the tropical rainforests located near the equator. These forests receive between 160 and 400 inches of rain per year. The total annual rainfall is spread pretty evenly throughout the year, and the temperature rarely dips below 60 degrees Fahrenheit. This steady climate is due to the position of rainforests on the globe. Because of the orientation of the Earth’s axis, the Northern and Southern hemispheres each spend part of the year tilted away from the sun. Since rainforests are at the middle of the globe, located near the equator, they arc not especially affected by this change. They receive nearly the same amount of sunlight, and therefore heat, all year. Consequently, the weather in these regions remains fairly constant. The consistently wet, warm weather and ample sunlight give plant life everything it needs to thrive. Trees have the resources to grow to tremendous heights, and they live for hundreds, even thousands, of years. These giants, which reach 60 to 150 ft in the air, form the basic structure of the rainforest. Their top branches spread wide in order to capture maximum sunlight. This creates a thick canopy (树冠) level at the top of the forest, with thinner greenery levels underneath. Some large trees grow so tall that they even tower over the canopy layer. As you go lower, down into the rainforest, you find less and less greenery. The forest floor is made up of moss, fungi, and decaying plant matter that has fallen from the upper layers. The reason for this decrease in greenery is very simple the overabundance of plants gathering sunlight at the top of the forest blocks most sunlight from reaching the bottom of the forest, making it difficult for robust plants to thrive.The Forest for the Trees The ample sunlight and extremely wet climate of many tropical areas encourage the growth of towering trees with wide canopies. This thick top layer of the rainforest dictates the lives of all other plants in the forest. New tree seedlings rarely survive to make it to the top unless some older trees die, creating a "hole" in the canopy. When this happens, all of the seedlings on the ground level compete intensely to reach the sunlight. Many plant species reach the top of the forest by climbing the tall trees. It is much easier to ascend this way, because the plant doesn’t have to form its own supporting structure. Some plant species, called epiphytes, grow directly on the surface of the giant trees. These plants, which include a variety of orchids and ferns, make up much of the understory, the layer of the rainforest right below the canopy. Epiphytes are close enough to the top to receive adequate light, and the runoff from the canopy layer provides all the water and nutrients(养分)they need, which is important since they don’t have access to the nutrients in the ground. Stranglers and Buttresses Some epiphytes eventually develop into stranglers. They grow long, thick roots that extend down the tree trunk into the ground. As they continue to grow, the roots form a sort of web structure all around the tree. At the same time, the strangler plant’s branches extend upward, spreading out into the canopy. Eventually, the strangler may block so much light from above, and absorb such a high percentage of nutrients from the ground below, that the host tree dies. Competition over nutrients is almost as intense as competition for light. The excessive rainfall rapidly dissolves nutrients in the soil making it relatively infertile except at the top layers. For this reason, rainforest tree roots grow outward to cover a wider area, rather than downward to lower levels. This makes rainforest trees somewhat unstable, since they don’t have very strong anchors in the ground. Some trees compensate for this by growing natural buttresses. These buttresses are basically tree trunks that extend out from the side of the tree and clown to the ground, giving the tree additional support. Rainforest trees are dependent on bacteria that are continually producing nutrients in the ground. Rainforest bacteria and trees have a very close, symbiotic (共生的) relationship. The trees provide the bacteria with food, in the form of fallen leaves and other material, and the bacteria break this material down into the nutrients that the trees need to survive. One of the most remarkable things about rainforest plant life is its diversity. The temperate rainforests of the Pacific Northwest are mainly composed of a dozen or so tree species. A tropical rainforest, on the other hand, might have 300 distinct tree species.All Creatures, Great and Small Rainforests are home to the majority of animal species in the world. And a great number of species who now live in other environments, including humans, originally inhabited the rainforests. Researchers estimate that in a large rainforest area, there may be more than 10 million different animal species. Most of these species have adapted for life in the upper levels of the rainforest, where food is most plentiful. Insects, which can easily climb or fly from tree to tree, make up the largest group (ants are the most abundant animal in the rainforest). Insect species have a highly symbiotic relationship with the plant life in a rainforest. The insects move from plant to plant, enjoying the wealth of food provided there. As they travel, the insects may pick up the plants’ seeds, dropping them some distance away. This helps to disperse the population of the plant species over a larger area. The numerous birds of the rainforest also play a major part in seed dispersal. When they eat fruit from a plant, the seeds pass through their digestive system. By the time they excrete (排泄) the seeds, the birds may have flown many miles away from the fruit-bearing tree. There are also a large number of reptiles and mammals in the rainforest. Since the weather is so hot and humid during the day, most rainforest mammals are active only at night, dusk or dawn. The many rainforest bat species are especially well adapted for this lifestyle. Using their sonar, bats navigate easily through the mass of trees in the rainforest, feeding on insects and fruit. While most rainforest species spend their lives in the trees, there is also a lot of life on the forest floor. Great apes, wild pigs, big cats and even elephants can all be found in rainforests. There are a number of people who live in the rainforests, as well. These tribes--which, up until recently, numbered in the thousands--are being forced out of the rainforests at an alarming rate because of deforestation.Deforestation In the past hundred years, humans have begun destroying rainforests at an alarming rate. Today, roughly 1.5 acres of rainforest are destroyed every second. People are cutting down the rainforests in pursuit of three major resources: · land for crops · lumber for paper and other wood products · land for livestock pastures In the current economy, people obviously have a need for all of these resources. But almost all experts agree that, over time, we will suffer much more from the destruction of the rainforests than we will benefit. The world’s rainforests are an extremely valuable natural resource, to be sure, but not for their lumber or their land. They are the main cradle of life on Earth, and they hold millions of unique life forms that we have yet to discover. Destroying the rainforests is comparable to destroying an unknown planet we have no idea what we’re losing. If deforestation continues at its current rate, the world’s tropical rainforests will be wiped out within 40 years. As we are still ignorant of millions of unique life forms in the rainforest, deforestation can be compared to the destruction of ______.
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