天山－3－37

Because mining and refining nickel is costly, researchers have developed an alternative method for extracting nickel using Streptanthus polygaloides, a plant that absorbs and stores nickel form the soil as it grows. The researchers incinerated a crop of Streptanthus they grew in nickel-rich soil. By chemically extracting nickel from the ash, they produced 100 pounds of nickel per acre of land at a total cost per pound slightly above that of current mining.

Wich of the following, if true, most strongly supports the conclusion that the use of Streptanthus to extract nickel will be commercially adopted?

A The season in which the researchers grew Streptanthus was an unusually favorable one, wiht the right amount of precipitation to maximize the growth rate of Streptanthus.

B Because lowering the concentration of nickel in the soil can make land much better for agriculture in general, a plot on which Streptanthus has been grown and harvested can be sold for substantially more than it cost.

答案是B. 但我认为应是A.   B是无关选项。说的是SOIL- PLOT 可以卖好价钱。而文中是把ST这种东西烧成灰，用化学过程过滤。所以只有ST长得多才支持结论。

题目问的是那个选项能使这一新的提炼过程更具有经济可行性，

b就正好支持了这一点。

支持；挖掘提取n很花錢，研究者發明一種可供選擇得方法～～～；然而化學提取n僅僅比原來方法便宜一點點！問題：支援化學方法經濟上更能被接受！b提取得n得土地更好種，化學方法中得樹還能賣錢。