求教prep07 test1里面两道题～～谢谢大家～～

Kateez

求教prep07 test1里面的两道题。
Most of the world's supply of uranium currently comes from mines.  It is possible to extract uranium from seawater, but the cost of doing so is greater than the price that uranium fetches on the world market.  Therefore, until the cost of extracting uranium from seawater can somehow be reduced, this method of obtaining uranium is unlikely to be commercially viable.                                                                            
Which of the following would it be most useful to determine in evaluating the argument?                                                                                           (A) Whether the uranium in deposits on land is rapidly being depleted
(B) Whether most uranium is used near where it is mined
(C) Whether there are any technological advances that show promise of reducing the cost of extracting uranium from seawater
(D) Whether the total amount of uranium in seawater is significantly greater than the total amount of uranium on land
(E) Whether uranium can be extracted from freshwater at a cost similar to the cost of extracting it from seawater
这道题我在C和正确选项A之间选了C。感觉两个都可行。我自己后来分析说能不能用对话的方式来解决，假如老板问我这句话，我觉得答A的话会跟对得商话，而答C则有点在扯话题，根本没有解决老板的问题。不知道大家有没有好的解释方向。我有点糊了。



20.For years the beautiful Renaissance buildings in Palitito have been damaged by exhaust from the many tour buses that come to the city.  There has been little parking space, so most buses have idled at the curb during each stop on their tour, and idling produces as much exhaust as driving.  The city has now provided parking that accommodates a third of the tour buses, so damage to Palitito's buildings from the buses' exhaust will diminish significantly.              


Which of the following, if true, most strongly supports the argument?        
(A) The exhaust from Palitito's few automobiles is not a significant threat to Palitito's buildings.
(B) Palitito's Renaissance buildings are not threatened by pollution other than engine exhaust.
(C) Tour buses typically spend less than one-quarter of the time they are in Palitito transporting passengers from one site to another.
(D) More tourists come to Palitito by tour bus than by any other single means of transportation.
(E) Some of the tour buses that are unable to find parking drive around Palitito while their passengers are visiting a site.
这题不是很明白C选项的意思，tour buses花费什么的时间比bus运送游客从一个地方到其他地方的时间的三分之一要少。有点弄不懂其与文章如何支持了？我选错的是D，的确是看不懂C，所以选了D，但是D有明显错误，就是与其他运输工具比较，扯谈，与原文无关。
我有时候经常遇到这种扯蛋读不懂选项C，但是其他选项都被我排除了，这个时候娘我应该咋办了？

HarrisZheng

1. 估计是听了gwd这个大忽悠的

什么老板对话？ 老板就一定个个思维敏锐啊？混乱的老板多了去了。


我们现在从真正逻辑角度来分析

简化一下 if not 降低成本，then 商业不可行 这是原句的条件及结论

C 选项 if 有 能降成本 则无法判断结论 （因为原命题的否命题真假不确定）
      if没有 不能降低成本 则支持结论

所以 c选项不行

再来看A 会耗尽 那甭管成本多高 就只有海里有了 削弱结论
       不会耗尽 支持结论

HarrisZheng

most buses have idled at the curb during each stop on their tour, and idling produces as much exhaust as driving.注意这句话
就是说在那里开车或不熄火的等待都一样造成污染

然后注意结论里的 will diminish significantly。会显著减少

C 选项说这些车超过3/4的时间都在 idle

那有停车场以后，这超过3/4的idle部分都被减掉了 自然显著减少污染伤害。

其实3/4这个数字是有意义的 如果这个数值很小 比如 5%，那么也就是说汽车95%的时间都在开着，那停车场就无法显著减少污染了

Kateez

谢谢HarrisZheng亲啊～～这样我的思路就清晰了～～谢谢谢谢谢～～