



7月11日 第一篇
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Question 39-41 Listen to a radio talk about fossil化石 fuels.# o! Q' ^ L/ d3 X! _8 K
Today I want to discuss fossil fuels, such as coal, oil and natural gas. The term ‘fossil fuel’ refers to the trapped remains of plants and animals in sedimentary沉积的 rock. You see, living plants trapped energy from the sun by the process of photosynthesis and (then) they store the energy in their chemical compounds. Most of that energy is released when the plant dies and decays. However, sometimes organic matter is buried, before it decays completely. In this way, some of solar energy becomes trapped in rocks-(has) hence the name: fossil fuel. Although the amount of organic matter trapped in any one growing season is small, (they) the accumulated remains (for) from millions of years are considerable. Because the accumulation rate is so slow-millions of times slower than (related) rate at which we (know decarp) now dig up this organic matter and burn it for energy-we must consider fossil fuels as nonrenewable resources. Tomorrow we’ll be discussing alternatives to fossil fuels that can be renewed.
2 N2 }, ~2 Y! r3 h& z, a# X! U7月11日 第二篇
4 D$ B7 d/ R$ \, a分类下 earth science 59 n3 x! [* {# H1 X4 e) g( [
Questions 40-43 Listen to part of talk in a geography class, g% k, `3 F+ D+ j: L0 D w
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Not long ago, some of you may have read about a team of mountain-climbing scientists (to have) who helped to recalculate the elevation of the highest mountain in the world: Mountain Everest珠穆朗玛. Of course, the elevation of Mountain Everest was determined many years ago using traditional surveying methods. But these scientists wanted to make a more precise measurement using a new method that takes advantage of recent advances in technology. It’s called the Global Positioning System.! O8 ?: J; E- C7 c/ V/ j5 i
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The Global Positioning System uses 24 (cite lines) satellites that circle the Earth. Each of these satellites is (consistently) constantly sending out signals. And each signal contains important information that can be used to determine the longitude, latitude and elevation of any point on the Earth’s surface. 9 R$ G2 U( M' z) M6 L# i
& y0 u6 \1 k- f+ l9 A8 PWell, in order to use this system to calculate Mountain Everest’s elevation, scientists needed to put a special receiver on its summit to receive the signals from the satellites. The problem (of) with this was that, in the past, the receivers were much too heavy for climbers to carry. But now these receivers have been reduced to about the size and weight (as) of a (hand) handheld telephone, so climbers was able to take a receiver to the top of Everest and from there, to access the satellites system signals that (were a lot) would allow them to determine the precise elevation. And it turns out that the famous peak is actually a few feet higher than was previously thought.
, N& w; ^6 t- ^' K; a; j$ w7月11日 第三篇
3 M# [1 s! z5 y( o+ A3 u分类下 earth science 6$ y5 S- @; _* x9 e
Questions 40-42 Listen to a talk in a geography class J9 Q! x1 m1 H, E0 v: p) F
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Now you’ve been reading articles about the tremendous damage done to life and property by earthquakes, that’s why seismologists have been working so hard to develop methods of earthquake prediction. We can now predict earthquakes (rarely) fairly well, but the predictions only locate potential areas of danger. They don’t predict the specific time and location (that had) at which an earthquake is likely to occur. Today I want to introduce to you three prediction models that have been developed.: [5 j0 ?# P4 u. N) Y; s1 @( u/ U
/ Q& j- c% N/ k3 HThe first prediction model looks along earthquake (fort) fault断层, those cracks in the earth’ crust, (the final) to find what are known as seismic gaps. Seismic gaps are places where (there have been) the fault has shown little or no seismic activity for a long time. This theory (pose) postulates假设 that such places are due for a major shock. 0 P* q! ]. r1 }/ w
+ p! R! e8 |( ^& DThe second model relies on phenomena-like ground tilt地斜. Using long cylindrical tubes圆柱管子 containing water, observers noted that ground tilt tended to occur before major earthquakes. That led them to correctly predicted the big High Chang quake in 1975, the first successful earthquake prediction scientists have ever made. A million people were evacuated撤退 from that Chinese city before the earthquake struck. Unfortunately, this method hasn’t work consistently, so we can’t say (its being effective) it’s been perfected.
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The third model is based on the theory that major earthquakes closely followed a series of minor ones. (Studying) Starting with the measurements and timing of the smaller quakes, a complex formula calculates the times of increased probability of a much larger quake. Right now, this method like the first method, can not predict specific times and places, but that may change as it is further developed.
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1 Y& ^- Y6 O7 A" g* oFor the moment, none of these models can predict with reasonable levels of confidence.