求助：feifeilogic/18

ozymendias

18. 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.

答案E。看了解释似乎也能理解。但不知为什么B不可行，B难道不能undermine argument当中针对passenger的这一点，证明argument当中的electronic devices不应加以限定么(e.g.飞机上固有的)？

linmeimei

原文  乘客用笔记本电脑  飞机当时正好失去信号
结论   电子设备（笔记本电脑）使飞机失去信号
B 选项      当前所使用的所有电子设备都对飞机的circuitry有影响  （即会使飞机失去信号）
B选项不正是对原文的加强么  
LZ体会一下我说的对不？

ozymendias

原文  乘客用笔记本电脑  飞机当时正好失去信号
结论   电子设备（笔记本电脑）使飞机失去信号
B 选项    ...
linmeimei 发表于 2011-3-25 20:57

    Thanks for your reply~

但是乘客用电子设备导致飞机失去信号在逻辑上不能推出电子设备让飞机失去信号，反之才成立。
In my humble opinion选项B强调了all，因此反驳了原文argument中passengers这一特定群体性。

huangsiyan

B is a strengthener since it corroborates the claim that electronic devices can interfere with circuit and points out that the electromagnetic radiation is the culprit.  Thus B make the conclusion in the argument more likely.

linmeimei

LZ你说的没错 但是你是在质疑原文啊  这是原文给出的信息，这里不是假设题 让你判断充分必要条件 原文和选项的正确性是毋庸置疑的，你应该紧扣 结论 对结论进行加强 这是根本问题 楼上说的很正确

brunhildS

E为何有undermine的作用？