GWD 28-28

rosebudxiaojie

28-28: 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. Possibly, 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说明金属全没活性了

E: the concentration of histidine in the growing herb declines as the plant approaches maturity

ANSWER: E

WHY NOT D?

rosebudxiaojie

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rosebudxiaojie

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titatita

我觉得选d

c无关

e随着herb的成熟,the concentration of histidine减少,可以理解为hitidine用于减少土壤的毒性,但也可以理解为只是减少,但并未对土壤毒素起作用,所以如果没有更好的选项是可以选e,

d经过一段时间,种植h的土壤可以适合原本会中毒的那些植物生长,非常直接地support了假设

redgrass

这道题应该是C才对。
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.
这句话说，herb是能生长在高金属土壤中植物的一种。
C说其他的others of the closely related group of plants 这种植物也生产 histidine ，那么可以推断 histidine也许是帮助这类型植物生活在高金属土的原因。

aircavalry

支持选C，理由：

C: others of the closely related group of plants are also found to produce histidine in large quantities

同类植物也produce大量的histidine，证明这是plants that thrive in soil with high concentrations of metals的共性，所以起到了支持的作用。注意黄底的词组，都可以在题干中定位。

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

herb长时间耕种在重金属环境中，将土质改善得适应其生长，这明显是他因，不是support而是undermine。

E: the concentration of histidine in the growing herb declines as the plant approaches maturity

只是在陈述一个事实，histidine随着herb的生长成熟而decline不能在逻辑上承接题目的假设。

[此贴子已经被作者于2007-11-23 9:54:01编辑过]