费费逻辑题一道 - ChaseDream

1. Modern navigation systems, which are found in most of today’s commercial aircraft, are made with low-power circuitry, which is more susceptible to interference than the vacuum-tube circuitry found in older planes. During landing, navigation systems receive radio signals from the airport to guide the plane to the runway. Recently, one plane with low-power circuitry veered off course during landing, its dials dimming, when a passenger turned on a laptop computer. Clearly, modern aircraft navigation systems are being put at risk by the electronic devices that passengers carry on board, such as cassette players and laptop computers.
Which one of the following, if true, LEAST strengthens the argument above?

(A) After the laptop computer was turned off, the plane regained course and its navigation instruments and dials returned to normal.
(B) When in use all electronic devices emit electromagnetic radiation, which is known to interfere with circuitry.
(C) No problems with navigational equipment or instrument dials have been reported on flights with no passenger-owned electronic devices on board.
(D) Significant electromagnetic radiation from portable electronic devices can travel up to eight meters, and some passenger seats on modern aircraft are located within four meters of the navigation systems.
(E) Planes were first equipped with low-power circuitry at about the same time portable electronic devices became popular.

b只说了所有电子设备都有辐射，但是没有说辐射是否足够影响飞机电路，所以比较象无关选项

e说明了便携式电子设备流行，流行必然造成乘客带上飞机是会经常发生的，影响飞机电路也是经常发生的，所以risky

同时发生的事情未必相关，就像两件事情一先一后也未必就有因果联系

选B。同意4楼的说法。别忘了，“Clearly, modern aircraft navigation systems are being put at risk by the electronic devices that passengers carry on board, such as cassette players and laptop computers. ”是文章的argument，portable electronic devices 的流行，显然会是使aircraft变得risky的

以下是引用kissadele在2008-2-18 11:53:00的发言：

我觉得是b

b只说了所有电子设备都有辐射，但是没有说辐射是否足够影响飞机电路，所以比较象无关选项

e说明了便携式电子设备流行，流行必然造成乘客带上飞机是会经常发生的，影响飞机电路也是经常发生的，所以risky

The low-power circuitry is more susceptible to interference than the vacuum-tube circuitry.

Evidence: The dials of a plane became dimming when a passenger turned on a laptop computer during landing.

Conclusion: modern aircraft navigation systems are being put at risk by the electronic devices that passengers carry on board, such as cassette players and laptop computers

文章所讨论的中心问题是关于电子设备所发出的电磁辐射对飞机电路的影响问题。

无论加强还是削弱，都必须围绕文章的中心展开。GMAT逻辑题目中很多错误选项属于看似与文章有关，但实属无关内容的选项。如本题E项，电子设备的流行与新的电路的运用时间上的统一对于电子设备可以干扰飞机飞行未建立起必然联系。而将两者相联系也是在我们自己经过推理后强加上去的联系。固然这些常识性的东西似乎是有道理的，但在GMAT考试中一定要摒弃这些自己固有的概念，牢牢把握文章中告诉我们的内容，紧紧抓住文章的逻辑关系，没有提到的切记不可妄自推理。而B项，给出所有电子设备在使用时会发射出可以干扰电路的电磁辐射的信息，这一点直接加强了文章结论 “ …at risk by the electronic devices that passengers carry on boar…” 。

其实这也是自己复习逻辑过程中的一点体会，整个逻辑关系才是最关键的，选择时一定要紧扣文章的逻辑关系。否则很容易上ETS给我们设下的圈套。