天山-3-37 非常迷人~~~

JerryGuan

Q37:

Because mining and refining nickel is costly, researchers have developed an alternative method for extracting nickel using Streptanthus polygaloides, a plant that absorbs and

stores nickel form the soil as it grows.  The researchers incinerated a crop of Streptanthus

they grew in nickel-rich soil.  By chemically extracting nickel from the ash, they produced 100 pounds of nickel per acre of land at a total cost per pound slightly above that of current mining.

Which of the following, if true, most strongly supports the conclusion that the use of

Streptanthus to extract nickel will be commercially adopted?

A.  The season in which the researchers grew Streptanthus was an unusually favorable one, with the right amount of precipitation to maximize the growth rate of Streptanthus.

B.   Because lowering the concentration of nickel in the soil can make land much

better for agriculture in general, a plot on which Streptanthus has been grown and harvested can be sold for substantially more than it cost.

C.   More air pollution is generated for each pound of nickel produced by extracting it from Streptanthus than is generated using conventional mining and refining.

D.  The land on which the researchers planted Streptanthus was unusually free of the various weeds that can compete with Streptanthus for water, nutrients, and sunlight.

E.   It is extremely rare for soil to contain higher concentrations of nickel than the concentrations present in the researchers’experimental plot.

这题太迷人了。。。不是因为美丽，而是它总让犯错。

给出的答案是B，我做的是D。我仔细看答案，后来渐渐明白了。

发出来讨论讨论。看看大家的见解。

joe11

Sexy questions

D. 没有weeds, 就像 A 一样，是 unusually favorable condition, 所以 A, D 就都排除了。

似水年华

选项D产生不了经济效益，而B可以产生。

linmonkey

我第一次做的时候都没太敢选B,觉得这个答案似乎太直白了,后来觉得其他的似乎不是很贴边,才选了个B

xealot

Actually, D kind of weakens the conclusion....

爱维的天

谁帮忙解释清楚一些…

到底Streptanthus这种植物是种植在nickel-rich soil还是一般的soil…

1284902

D是说试验采用的方法太好了，如果实际没那么好，就会提高成本，是削弱项。应为B

scorpio0001

以下是引用爱维的天在2004-12-29 13:13:00的发言：

谁帮忙解释清楚一些…

到底Streptanthus这种植物是种植在nickel-rich soil还是一般的soil…

从a plant that absorbs and stores nickel form the soil as it grows. 得出S这种植物是生长在一般的soil上的，之所以researcher把它种植在nickel-rich soil上是为了得到更多的nickel.

jackychew

我有一些疑问，大家解释一下。

做的时候来不及做了，随便选了B；分析的时候，很痛苦的选了E，一对答案，竟然还是B！

无论答案如何，讨论一下解题思路：怎么看B都不想是ETS出的正确选项，除非这道题分值比较低...另外，B还是有无关的感觉（原文中好像并没有提到experiment's process的费用就比current mining的低），因为题干中已经提到slightly above的优势了，再强调其他的经济效益也怎么都不为过。

E有没有可能支持呢:如果土壤中的concentration很少比新实验的方法高，说明新实验的方法没有浪费；否则的话可能存在一个它因削弱：即100pounds的nickle每磅含量高，但其消耗的原土用currrent mining可能产出200pounds的nickle。

原文中好像也并没有提到experiment's process的费用就比current mining的低，好多不确定因素，这题真不知道如何形成严谨的思维。望大家再详细地分析一下，谢谢。

yukon

顶一下，因为我也不懂。我当时做的时候时用排除法做的，就B看的云山雾罩，其它的都可以排除。