[求助]GWD-28-28

tania

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

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

我选了d，可是据说28题是新东方绿皮书上的，应该选E

原文结论是大量的histidine使得herb 能够在金属含量高的土壤里生存。问哪个选项支持？

现在仔细看看，觉得d也不是支持，herb的种植使得那些本不能在金属含量高的土壤中种植的植物也能生存，并不能说明就是histidine发挥了作用。可是为什么e是支持呢？e说植物成熟了，histidine的含量就降低了，这能支持是histidine发挥了作用吗？

请大家讨论

howardwang

C

smallball

可是C 中并没有说others of the closely related group of plants 生长在含大量metal 的土壤中啊，新东方的答案的确给的是E

smallball

我的理解是这样的：

一些植物生长在含大量metal的土壤中而不死的原因是分泌histidine

即：高histidine----->在高metal 土壤中生长

d 恰恰说反了，说的是high metal--->high histidine

e 偶也觉得有点疑惑，是说生长---->histidine下降 则表明plant 在生长过程中是消耗histidine吗？

还请牛牛指教！

howardwang

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 ______.

C: others of the closely related group of plants are also found to produce histidine in large quantities 从C可以得出，这类植物都有一个共同点。

当一类事物中有一个共同点（而且已经证明，这类事物中的一个事物的该共同点对事物的特征有作用，即： large amounts of histidine, an amino acid that, in test-tube solutions, renders these metals chemically inert.），且这类事物表现出一个共同的特征（a group of closely related plants that thrive in soil with high concentrations of metals that are toxic to most other plants.）。

那么，你能推出什么呢？

可能就是这个共同点造成了这个共同的特征。所以支持结论。

[此贴子已经被作者于2005-9-8 13:27:07编辑过]

smallball

以下是引用howardwang在2005-9-8 13:24:00的发言：

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 ______.

C: others of the closely related group of plants are also found to produce histidine in large quantities 从C可以得出，这类植物都有一个共同点。

当一类事物中有一个共同点（而且已经证明，这类事物中的一个事物的该共同点对事物的特征有作用，即： large amounts of histidine, an amino acid that, in test-tube solutions, renders these metals chemically inert.），且这类事物表现出一个共同的特征（a group of closely related plants that thrive in soil with high concentrations of metals that are toxic to most other plants.）。

不错，是共同的特征，但是并没有证明a group of closely related plants are also found to produce histidine in large quantities  是导致在高metal的土壤中生长的原因啊，怎么能用没有证明的东西，去证明待证明的东西呢？

牛牛如何看E呢？谢谢哦^^

[此贴子已经被作者于2005-9-8 13:57:46编辑过]

howardwang

题干中的：large amounts of histidine, an amino acid that, in test-tube solutions, renders these metals chemically inert. 不就是证明吗？

E 应该是无关选项。既不支持，也不削弱结论。

wwwhahchn

我选D，因为metals被弄得inert了，所以其他植物也能生长

smallball

以下是引用wwwhahchn在2005-9-8 16:22:00的发言：
我选D，因为metals被弄得inert了，所以其他植物也能生长

恩，我开始就是选的D，但是看了又看觉得D不对似的，就象楼主说的“现在仔细看看，觉得d也不是支持，herb的种植使得那些本不能在金属含量高的土壤中种植的植物也能生存，并不能说明就是histidine发挥了作用。”

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