[求助]GWD28－28

evonneangela

我发现没有人问这个题，可能大家都做对了，55555

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

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

很多人的答案都是A，可是我选得C。我想不通。谁能帮帮我啊?万分感谢

howardwang

你的选择应该正确

evonneangela

谢谢。那我就相信我自己先。下星期就要考试了。现在特别晕。只能说相信自己比较重要了。谢谢

howardwang

遇到任何困难，都要相信自己。这是取得好成绩的必要条件（当然最好是充分条件，或者充要条件，呵呵）。

祝你下周好运！

muzikfantasy

E取非是削弱，所以是加强：h在成熟前后消失都证明它不一定是植物含铁的原因，在时间上与金属的形成一致；C无效，虽然同类都有，但没建立起和h的联系（跟A是一个性质，联系是臆断的）。

铁甲

是选C啊.

逻辑关系是:1.这种植物在有毒的金属土壤中能成长,它含高浓度的某种氨基酸.

           2.其他种的植物能在有毒的金属土壤中能成长,发现它们含高浓度的某种氨基酸.

3.所以含高浓度的某种氨基酸可能是植物在有毒的金属土壤中能成长的原因.

yangxiaogang

支持C

z520m

C是无关吧！这里说的是herb,C说到了其它同类植物，这不能说明什么吧！E感觉也不对，它成熟了之后分泌减少了不能说明这种分泌物帮助成长吧？应该选D.D成立就说明这种植物的这个renders these metals chemically inert的h能够改变土壤。请大牛出来给出信服答案，我的答案也不一定对。

mumu1234

以下是引用铁甲在2005-11-16 9:55:00的发言：

是选C啊.

逻辑关系是:1.这种植物在有毒的金属土壤中能成长,它含高浓度的某种氨基酸.

           2.其他种的植物能在有毒的金属土壤中能成长,发现它们含高浓度的某种氨基酸.

3.所以含高浓度的某种氨基酸可能是植物在有毒的金属土壤中能成长的原因.

davidchow

文章的conclusion是the herb's high histidine production is what allows it to grow in metal-rich soils,所以c是无关的。

其实这归根结底是个加强题，加强题只要直接加强结论就可以了，所以选a比较准确，histidine is found in all parts of the plant – roots, stem, leaves, and flowers说明histidine production高，很自然的对结论起到了一个support的作用