GMAT真题:2010年8月阅读（至8.29）（十三）
2011-09-19 19:56:00   来源：网络资源    双击单词自动翻译

　　1.2.3. 测Mount Everest 的高度*

　　AppleStrudel(730)

　　测珠峰(Mount Everest)高度(两段):

　　首段：某年，中国重新测了珠峰，用的是传统的目测法(Visibal….). 此方法是目测什么海拔仪，但是目测时是透过光线的折射读数，(大概是像温度计一样读数的)因为空气状况会随温度和压力变化，此读数不精确。为了减小误差，测量队尽量来到离峰顶只有几迈到十几迈的地方。(此处有题：答案就是离峰顶更近)。

　　二段：测量中在三点上改进了此传统方法。第一，。。。;第二，。。。;第三，用红旗子标记了以前测量点，下次确定还在这点测量(很好懂，第一段有关于仪器的描述有点晕，但是不需要看懂)

　　[GWD]

　　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。