请教OG 11 版 逻辑 113题

113

The difficulty with the proposed high-speed train line is that a used plane can be bought for one-third the price of the train line, and the plane, which is just as fast, can fly anywhere. The train would be a fixed linear system, and we live in a world that is spreading out in all directions and in which consumers choose the free-wheel systems (cars, buses, aircraft), which do not have fixed routes. Thus a sufficient market for the train will not exist.

Which of the following most severely weakens the argument presented above?

A.     Cars, buses and planes require the efforts of drivers and pilots to guide them, whereas the train will be guided mechanically.

B.     Cars and buses are not nearly as fast as the high speed train will be.

C.     Planes are not a free wheel system because they can fly only between airports, which are less convenient for consumers than the high-speed train’s stations would be.

D.    The high speed train line cannot use currently underutilized train stations in large cities.

E.     For long trips, most people prefer to fly rather than to take ground-level transportation.

为什么选C，想不通。C不是等于反对前提了吗？

B为什么不对？

说实话这道题我就没有看出来是要把火车和飞机比，还是火车和Cars and buses比,还是火车和所有其他交通方式比。惭愧。。。

请各位指点，万分感谢！！

怎么没人答？5555555

主要论据：主要是飞机和火车对比

1、一样快，飞机价格低

2、train - fixed linear system ，aircraft - free-wheel systems，People like to choose the latter one

结论：a sufficient market for the train will not exist

解：一般能反驳其中一条论据的就能weaken

C Planes are not a free wheel system because they can fly only between airports, which are less convenient for consumers than the high-speed train’s stations would be.

反驳的是第二条——Planes are not
                a free wheel system，题点和关键词 都出来了，后面是细述理由，SO是正确答案拉

B.     Cars and buses are not nearly as fast as the high speed train will be.

之前的比较中，车车和巴士与火车的速度没有做过比较，算作无关项

我对这题也不理解，请明白的人出来解释解释！

C选项明显就是反对原文论据啊，虽然说新东方说过weaken是削弱结论，但我决不是盲目相信新东方，我觉得说得很对啊，原文都把这个作为一个既定事实在叙述了，怎么能去否定前提呢？

而且我觉得A虽然提到的guide在原文没有出现，但提出另一个事实说明火车有其相对那些free-wheel system的交通工具的优势，不正削弱了结论——火车没市场吗？而且A只是削弱了结论，而没有改动前提，这不是更好吗？ 

我感觉题目中的can fly anywhere，这个anywhere指得是大地点的anywhere，比如说北京--上海，而C中说到了这种意义的anywhere只限于airport之间，而不能连通两个小地点，比如说北京--天津，所以飞机并没有预期的那样比火车便利，直接否定了原文的前提。

否定前提可以很好的削弱结论。The conclusion is based on the premise. when the premise is not true, the conclusion, of couse, is ungrounded.

A也可以作为他因来削弱结论，但是无人驾驶究竟能为火车运输市场做出多大的贡献并没有说明，没有直接把原文的前提否定杀伤力大。

我感觉如果Weaken中有否定前提，也有他因，否定前提的力度应该更大。

不知道大家是怎么认为的：）

我也不明白，我觉得A也可以啊

谢谢julianfl斑竹，我仔细想了一下，按照A选项，如果火车只是比飞机好在无人驾驶，只能说明火车多了一个优点，不能说明火车是必须的，但按照C选项，有些地方无法建飞机场，但可以建火车站，那么火车就是必须的。

但我还是有点不明白，原文到底比较的是高速火车与飞机，还是火车作为固定线路系统与free-wheel system比较？我总觉得原文第二句话是把两种系统作比较，飞机只是free-wheel system的一个例子，所以即使飞机场比火车站方便，那汽车不是比火车站更方便吗？

OG的解释可以看出比较的是飞机和火车（对B选项的解释）但我就不知道大家到底是怎么看出它比较的只是飞机和火车，不是两种系统？