求助贴,老题目了,寻真正高手给真正答案

Rebeldom

Which of the following most logically completes the argument?
A certain cultivated herb is one of a group of closely related plants that thrive in soil with high concentrations of metals that are toxic to most other plants.  Agronomists studying the herb have discovered that it produces large amounts of histidine, an amino acid that, in test-tube solutions, renders these metals chemically inert.  ossibly, therefore, the herb’s high histidine production is what allows it to grow in metal-rich soils, a hypothesis that would gain support if ______.
A.    histidine is found in all parts of the plant—roots, stem, leaves, and flowers
B.    the herb’s high level of histidine production is found to be associated with an unusually low level of production of other amino acids
C.    others of the closely related group of plants are also found to produce histidine in large quantities
D.    cultivation of the herb in soil with high concentrations of the metals will, over an extended period, make the soil suitable for plants to which the metals are toxic
E.    the concentration of histidine in the growing herb declines as the plant approaches maturity

crazysalad

我觉得选E，histidine是用于帮助生长的，更符合therefore后面那句话。而C虽然提及了这一组的plants都具有此特性，但是与therefore后面的关系没有E大。

kevin0214

应该选C吧，D 肯定是不对的，楼上都解释了
唯一迷惑的就是E，怎么看这个都是无关了，但是就有一种感觉它无关得太突兀了，想让人尝试解释它，比如说它成熟之后就死了，所以不需要再分泌histidine来抗金属了，但是题干显然没有提供此类信息，所以我们不能假设
所以应该是C吧，虽然C也不能确保结论的正确，因为相关的植物都有大量histidine可以做很多解释，比如有另一种物质X可以以抵抗金属，而X会引起histidine的分泌增加。但是结合histidine可以inert metal，C确实是support了结论

santaalex

C 其实是个变向的同因同果  other plants 也 produce 所以 也能在金属土壤中生存 即加强了本身的hypothesis

流浪的心

D是不对的

D的意思是：在有高浓度金属的土地里面种herbal，时间长了会让这个土地适合种植物，那些植物金属对他们来说是有害的

而需要证明的是：高histidine是让herbal在多金属土地生长的原因

D完全没有提到herbal自身的情况，很难推到结论吧。

holacraig

我选D，这种Herb产生的histidine可以是金属惰性的（不知道应不应该这么解释），那如果将herb种在金属含量高的土壤中，一段时间后，这块土壤就会适合种植对金属“过敏”的植物。C的话，虽然也能起支持作用，但是即使这些类似的植物没有在被发现produce histidine in large quantities，也不起削弱作用吧。

gracezz

我也选了C~~

Rebeldom

E其实也是无关的,成长的过程中histidine含量的降低
并不能说明histidine是植物可以生长在高金属土壤中的原因
C的确提高了整个ARGUMENT成立的概率,因为第一句的因素
A certain cultivated herb is one of a group of closely related plants that thrive in soil with high concentrations of metals that are toxic to most other plants
通过第一句话可以看出C的确最好,提高了概率

Rebeldom

选D不对,
结论是要证明the herb’s high histidine production is what allows it to grow in metal-rich soils
D选项是说,植物种在高金属含量土壤里可以逐渐使得土壤适合植物生长,没有提到植物本身的属性

costan

Which of the following most logically completes the argument?
A certain cultivated herb is one of a group of closely related plants that thrive in soil with high concentrations of metals that are toxic to most other plants.  Agronomists studying the herb have discovered that it produces large amounts of histidine, an amino acid that, in test-tube solutions, renders these metals chemically inert.  ossibly, therefore, the herb’s high histidine production is what allows it to grow in metal-rich soils, a hypothesis that would gain support if ______.
A.    histidine is found in all parts of the plant—roots, stem, leaves, and flowers
B.    the herb’s high level of histidine production is found to be associated with an unusually low level of production of other amino acids
C.    others of the closely related group of plants are also found to produce histidine in large quantities
D.    cultivation of the herb in soil with high concentrations of the metals will, over an extended period, make the soil suitable for plants to which the metals are toxic
E.    the concentration of histidine in the growing herb declines as the plant approaches maturity

-- by 会员 Rebeldom (2010/5/16 16:48:07)

我选C。