In 1975 Chinese survey teams 1975年中国人量度珠峰，使用的 remeasured Mount Everest, the highest 技术和1852年英国人的相同。 of the Himalayan mountains. Like the 他们从海岸线开始行进，每隔几 Line British in 1852, they used the age-old 步量度一次上升高度。 (5) technique of “carrying in” sea level: surveyors marched inland from the coast for thousands of miles, stopping at increments of as little as a few feet to measure their elevation, and mark- (10) ing each increment with two poles. To measure the difference in elevation 使用工具：置于两根杆中间的望 between poles, surveyors used an 远镜。 optical level—a telescope on a level base—placed halfway between the (15) poles. They sighted each pole, read- ing off measurements that were then used to calculate the change in eleva- tion over each increment. In sight of 看到峰顶时，他们使用经纬仪 the peaks they used theodolites— 探定顶点的上升。 (20) telescopes for measuring vertical and horizontal angles—to determine the elevation of the summit. The Chinese, however, made 但中国人努力改正英国人的误 efforts to correct for the errors that 差。 (25) had plagued the British. One source 误差1：由于不同温度压力造成 of error is refraction, the bending of 的光折射。这会产生峰顶幻象。 light beams as they pass through air layers of different temperature and pressure. Because light traveling. (30) down from a summit passes through many such layers, a surveyor could sight a mirage rather than the peak itself. To reduce refraction errors, the 解决：1，减少通过经纬仪的光， Chinese team carried in sea level to 2，使用天气气球测量温度压力。 (35) within five to twelve miles of Everest’s summit, decreasing the amount of air that light passed through on its way to their theodolites. The Chinese also launched weather balloons near their (40) theodolites to measure atmospheric temperature and pressure changes to better estimate refraction errors. Another hurdle is the peak’s shape. 误差2：测量者们的测量点不同。 When surveyors sight the summit. (45) there is a risk they might not all measure the same point. In 1975 the Chinese installed the first survey 解决：安装一个红色灯塔。 beacon on Everest, a red reflector visible through a theodolite for ten (50) miles, as a reference point. One 误差3：海平面不平。 more source of error is the uneven- ness of sea level. The British assumed that carrying in sea level would extend an imaginary line from (55) the shore along Earth’s curve to a point beneath the Himalaya. In reality, sea level varies according to the irregular interior of the planet. The Chinese used a gravity meter to 解决：用重力计改正误差。 correct for local deviations in sea level. ------------------------------------------------------------- Q32 It can be inferred from the passage that refraction would be most likely to cause errors in measurements of a mountain’s elevation under which of the following conditions? A. When there are local variations in sea level B. When light passes through humid air C. When theodolites are used relatively far from the mountain peak. D. When weather balloons indicate low air temperature and pressure. E. When sea level has been carried in to Within five to twelve miles of the summit.
------------------------------------------------------------- Q33 Which of the following best describes the purpose of the sentence in lines 23-25 (“The Chinese…the British”)? A. Introduce a definition B. Signal a transition in focus C. Summarize the preceding paragraph D. Draw a contrast between two different theories. E. resent information that contradicts the Preceding paragraph.
---------------------------------------------------- Q34 Which of the following is NOT mentioned as a possible source of error in surveying mountain elevation? A. Mirages B. Refraction C. Inaccurate instruments D. Variations in sea level E. Uncertainty about the exact point to be Measured
--------------------------------------------------- Q35 The primary purpose of the passage is to A. provide details about improvements to a process B. challenge the assumptions underlying a new method C. criticize the way in which a failed project was carried out D. call for new methods to solve an existing problem E. explain the theory behind a new technique
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发表于 2010-8-25 09:55:12
resent information that contradicts the