文章作者 100test 发表时间 2007:11:14 12:43:53
来源 100Test.Com百考试题网
解决方案一:古代湖泊水位法One very old(大-) method*2C used in the investigation of past climatic conditions involves the measurement of water levels in ancient lakes. 原因一In temperate regions温带地区, there are enough lakes for correlations between them to give us a reliable(小 ,由于前面有大,所以后面一定有转折) picture. In arid and semiarid regions, on the other hand(转折), the small number of lakes and the great distances between them reduce the possibilities for correlation. 原因二Moreover(大列举的非第一点), since lake levels are controlled by rates of evaporation as well as(强调前者) by precipitation降水, the interpretation of such levels is ambiguous*5B(-). For instance(与结论紧密相连,篇幅小,可以暂时不看), the fact that lake levels in the semiarid southwestern United States*5 appear to have been higher during the last ice age than they are now was at one time attributed to increased precipitation. On the basis of snow-line elevations*3, however(其实还是紧跟上一个例子,可以暂时不看), it has been concluded*3 that the climate then was not necessarily wetter than it is now, but rather that both summers and winters were cooler, resulting in reduced evaporation*3E.
解决方案二:花粉法Another problematic(大-) method is to reconstruct former climates on the basis of pollen profiles. The type of vegetation in a specific region is determined by identifying and counting(by doing通常都是很重要的内容) the various pollen grains found there. Although(转折的前半句可以不读) the relationship between vegetation and climate is not as direct as the relationship between climate and lake levels, the method often works well(小 ) in the temperate zones. In arid and semiarid regions in which there is not much vegetation(-), however, small changes in one or a few plant types can change the picture dramatically, making accurate correlations between neighboring areas difficult*8A(-) to obtain.
缺正确解决方案:看过程不看结果
1. Which of the following statements about the difference between marine and continental sedimentation*1 is supported by information in the passage?