阅读狗狗有一篇关于重新测定珠峰高度的文章，我在GWD中做到了，不知道是不是一样，大家看看，希望有帮助
AppleStrudel（730）（altitude，elevation）
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(refraction)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。
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 thatrefraction would be most likely to cause errors in measurements of a mountain’selevation under which of the followingconditions?
A.When there are local variations in sealevel
B.When light passes through humid air
C.When theodolites are used relatively farfrom the mountain peak.
D.When weather balloons indicate low airtemperature 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 thepurpose 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.Present 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 bemeasured
---------------------------------------------------------------
Q35: The primary purpose of the passage is to
A.provide details about improvements to a process
B.challenge the assumptions underlying anew method
C.criticize the way in which a failed projectwas carried out
D.call for new methods to solve an existing problem
E.explain the theory behind a new technique
我在GWD阅读翻译上看的是DBCA
但是在GWD答案上看的是CBCA~ 具体大家讨论~
引用别人：古人讨论：
我认为是C，原文：the Chinese team carried in sea level to within five to twelve miles of Everest’s summit, decreasing the amount of air that light passed through on its way to their theodolites.
是说把范围控制在离summit某个范围可以减少光的通过，那么c说离summit相对远正是这个的取非。
而D，原文说的是通过测压力的变化可以估计折射，而不是压力的大小改变准确性。
另外常理，压力越小，对于空气越少，光的折射影响越小，误差越小。 | 
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发表于 2010-8-25 09:28:34
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