90年4月（短阅读）

yuanleiliangUID: 2866246

　　　Because of its accuracy in outlining
　　the Earth's subsurface, the
　　seismic-reflection method（关键词，对应17题中的techinique） remains the
　　most important tool in the search for
(5) petroleum reserves.（开头即是全文主旨句）In field practice,a
　　subsurface is mapped by arranging a
　　series of wave-train sources, such as
　　small dynamite explosions,in a grid
　　pattern. （讲述方法的具体使用，感觉之后的部分可以采用快速阅读的方法）As each source is activated,
(10) it generates a wave train that moves
　　downward at a speed determined uniquely
　　by the rock's elastic characteristics(石头的弹性特征对该方案有影响).
　　As rock interfaces are crossed,the
　　elastic characteristics encountered
(15) generally change abruptly, which causes
　　part of the energy to be reflected back
　　to the surface, where it is recorded by
　　seismic instruments. （该句话描述弹性特征是如何影响该方案的）The seismic records
　　must be processed to correct for
(20) positional differences between the
　　source and the receiver, for unrelated
　　wave trains, and for multiple
　　reflections from the rock interfaces.
　　Then the data acquired at each of the
(25) specific source locations are combined
　　to generate a physical profile of the
　　subsurface, which can eventually be used
　　to select targets for drilling.

17.The passage is primarily concerned with（TS）
(A)describing an important technique
(B)discussing a new method(并没有出现新老观点对比)
(C)investigating a controversial procedure(找不到controversial点)
(D)announcing a significant discovery(discovery表明以前没有，现在才发现,换言之，还是一种新东西，意思仍旧与B选项一致)
(E)promoting a novel application(新的应用，跟B选项是一个意思)

18　According to the passage, in the seismic-
reflection method all of the following
have a significant effect on the signal
detected by the seismic instruments
EXCEPT the（哪个对采集到的信号没有影响）
(A)presence of unrelated wave trains（对应22行）
(B)placement of the seismic instruments（对应18行）
(C)number of sources in the grid pattern
(D)nature of the reflectivity of the rock
interfaces（对应14行）
(E)properties of rocks through which the
wave train has traveled（DE都有说石头的特性，定位至文章13句）

本题我错选了D项，当时也没有仔细读懂题目就是要考的是什么，待到现在分析的时候，才明确对采集信号有影响的因素。
C选项跟影响因素无关，所出现的位置也不再影响因素的那一句内。

19 　It can be inferred from the passage that
the seismic-reflection method would be
likely to yield an inaccurate physical
profile of the subsurface in which of the
following circumstances?（哪个选项会导致测量的不准确）
(A)If the speed at which the wave train
moved downward changed（速度变化）
(B)If the receiver were not positioned
directly at the wave-train source（接收方与源的位置变化，定位到14行）
(C)If the rock on one side of a rock interface
had similar elastic characteristics to those
of the rock on the other side
(D)If the seismic records obtained for
the different sources in a grid were highly
similar to each other（）
(E)If there were no petroleum deposits
beneath the area defined by the grid of
wave-train sources

20　Which of the following best describes
the organization of the passage?（考的文章结构）
(A)A method is criticized, and an alternative
is suggested.
(B)An illustration is examined, and some
errors are exposed.
(C)An assertion is made, and a procedure is
outlined.（方案的声明及其步骤描述）
(D)A series of examples is presented, and a
conclusion is drawn.
(E)A hypothesis is advanced, and supporting
evidence is supplied.

　　由于“地震反射法”在勾画地球的地面下部位这方面的准确性，该方法一直是探寻石
油储存的最重要的工具。（本章主旨题，是一个说明性的文体，阐述一种方法）在实地作业中，通过将一系列波列源，诸如小规模炸药爆炸，排
列成为一网格模式，从而将地面下部位在地图上标绘出来。（对该方法的简要介绍）随着每一个波列源得以被触发，
它就产生一个波列，该波列便以一特定速度向下移动，而其下移的速度仅仅取决于岩石的
弹性特征。随着岩石的界面被穿越，所遇的弹性特征一般会突然地改变，这便导致一部分
能量反射回到地面，于是这部分能量就在地面被地震仪器记录下来。地震记载必须加以处
理，以便纠正波列源与接受器之间的位置差异，纠正无关的波列，以及纠正来自岩石界面
的多重反射。然后，在每一个特定波列源位置获取的数据被综合起来，得出一个地面下部
位的物理剖面图，而这一剖面图则能最终用来择取目标进行钻探。（详细介绍）

以上是我对照坛子前辈所做的阅读总结，肯定不全面，也肯定有很多分析总结不到位的地方，如果有发现错误的说法，麻烦大家给指出来！
后来分析的时候，发现19题不会做了，都不知道当时是怎么选正确的？如果有人有好的思路，还望给在下一些指点，在此谢过！

ep6h123UID: 2960051

mark

永动鸡UID: 3006486

d

hangweiqiangUID: 3478097

我对于第18题有个疑惑，如果信号源对收集的信号没有影响的话，干嘛还要放a series of wave-train sources，一个也一样啊