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.）。 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。 GG说得很好,我觉得这些植物共同特点是它们都能在高金属的土壤中生存文章说其中的一种HERB含有H物质,H在实验室试验中可以驱除金属的活性 结论:H物质是使这一种植物能在高金属土壤中生存的原因 问如何支持 A: histidine is found in all parts of the plant – roots, stem, leaves, and flowers Agronomists studying the herb have discovered that it produces large amounts of histidine,重复文中的话,有时可以作为加强来看,但不是最好的选项,先隔着.
Agronomists studying the herb have discovered that it produces large amounts of histidine,重复文中的话,有时可以作为加强来看,但不是最好的选项,先隔着. 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 无关,和别的氨基酸没有关系
无关,和别的氨基酸没有关系 C: others of the closely related group of plants are also found to produce histidine in large quantities 作为同能在特殊土壤中存活的植物们,它们都具有另一共同的特点----生产H物质.那么H物质就应该是存活的共同原因 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 D项说的是H的确能消除土壤中金属的活性,再次重复了文中实验室试验结果,效果和A一样 E: the concentration of histidine in the growing herb declines as the plant approaches maturity 无关,我觉得这项还有削弱的作用,因为H物质在后期越来越少,对金属的作用也更加微弱,植物仍可以生存,那么H可能不是其生存的原因
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发表于 2005-9-22 13:45:00
