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? 结构: low-power circuitry比vacuum-tube circuitry更易受干扰(前提),所以,当飞机上有电子设备(A).,飞机是危险的.(B),因果结构
(A) After the laptop computer was turned off, the plane regained course and its navigation instruments and dials returned to normal. 没有A , 就没有B (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. 没有A , 就没有B
(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. A 是有存在的, 加强A (E) Planes were first equipped with low-power circuitry at about the same time portable electronic devices became popular. 无关选项 我好像总是找不准结论是什么,原因是什么,特别是背景信息比较多的时候, 有没有什么好的办法解决这个问题 对于这到题,我的分析正确吗? A 推出B 结构的题目, 对于strengthens来说, 没有A ,就没有B ,是不是一种架桥式的加强
郁闷,逻辑题是我的痛楚!!!!!!!!!!!!!! | 
