请教GWD 31-16

shellsnow

16: In recent years, networks of fiber-optic cable have been replacing electrical wire for transmitting telecommunications signals. Signals running through fiber-optic cables deteriorate, and so the signals must be run through a piece of equipment called a regenerator before being transmitted father. Light-Line is the leading manufacturer of signal regenerators. Therefore, Light-line is one of the companies that will most benefit if new long-distance fiber-optic telecommunications networks are constructed.

Which of the following, if true, casts the most doubt on the prediction about light-ling’s prospects?

A: Telecommunications signals sent along electrical wires can travel much farther than signals transmitted through fiber-optic before needing to be regenerated.

B: Expanding its production of regenerators will require Light-line to spend proportionately more on labor and materials.

C: The volume of signals that a fiber-optic cable can carry is several thousand times greater than the volume that can be carried by an electrical wire of similar size.

D: There are technologies that enable telecommunications signals to be transmitted without either wire or fiber-optic cable.

E: Several manufacturers are developing regenerator technologies that will allow signals to be transmitted many times farther than at present before requiring regeneration.

请问这个题目中E,D,B的区别，我觉得三个答案都有可能对阿，是在糊涂了，恳请大家指点

jackzhu69

TO:lunabird

文中结论：Therefore, Light-line is one of the companies that will most benefit if new long-distance fiber-optic telecommunications networks are constructed.已经确认需要采用fiber-optic技术了，此处无法采用断桥法来削弱结论。

laihong

选E吧.题目说如果new long-distance fiber-optic telecommunications networks are constructed. 那么该公司收益, D说不用fiber-optic ,  所以无关. B支持, 因为公司能够获得这工程, 而简单地说材料和劳动成本成比例增加,不能推出公司不获利.E说其他公司可能会抢走这工程

boyray

比较下来也只有E了

其实感觉E也不是最完美，因为题目中说过Light-line is one of the companies that will most benefit... 本来就没有排除其他公司。

jjll

D为什么不可以？如果D正确的话，fire-optic都不会建了，那不就是cast most doubt on the prediciton about lightline's prospects?

请NN参加讨论。

sunnybest

同意4楼的观点,我也选D.

其他公司也会从中获利与L公司获利本来就不矛盾呀,文中明确指出L是获利最多的公司之一,并不具有排他性呀!

铁甲

D只是说存在一种无线技术,但是这种技术能否给光纤技术带来威胁?没有提到.所以无关

hy903

我选d, 因为e最后说是before requiring regeneration. 无关。

hy903

我选d, e最后说before requiring regeneration.，无关

lunabird

选D没错。

因为（1）“Signals running through fiber-optic cables deteriorate, and so the signals must be run through a piece of equipment called a regenerator before being transmitted father.”（2）“Light-Line is the leading manufacturer of signal regenerators.”所以文中推理该公司会从中获益。现在找削弱，就是公司不会从中获益。

D说新的技术使signals to be transmitted without either wire or fiber-optic cable，获益前提中（1）已经不存在了，所以，公司不会获益，消弱！