XDF-178
which of the following most logically completes th argument
a certain cultivated herb is one of a group of closely related plants that thrive in soil with high concerntrations 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. Possibily, therefore, the herb's high histidine production is what allows it to grow in metal-high 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.other 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
答案选e， 但我觉得选c， 因为c说明了其他植物具有和herb一样的特点，这样就加强了是"histidine"这个因素使得herb能在这种土壤中生存
XDF-182
Advertisement: For sinus pain, three out of four hospitals give their patients Novex. So when you want the most effective painkiller for sinus pain, Novex is the one to choose.
Which of the following, if true, most seriously undermines the advertisement’s argument?
(A) Some competing brands of painkillers are intended to reduce other kinds of pain in addition to sinus pain.
(B) Many hospitals that do not usually use Novex will do so for those patients who cannot tolerate the drug the hospitals usually use.
(C) Many drug manufacturers increase sales of their products to hospitals by selling these products to the hospitals at the lowest price the manufacturers can afford.
(D) Unlike some competing brands of painkillers, Novex is available from pharmacies without a doctor’s prescription.
(E) In clinical trials Novex has been found more effective than competing brands of painkillers that have been on the market longer than Novex.
本题选d， 谁能解释一下，医院为什么更喜欢给病人开非处方药. | 
