[求助] prep2一道逻辑题

faynie

114.
            (29014-!-item-!-188;#058&003730)     (GWD 12-Q38)

 

Outbreaks of Rift Valley fever occur irregularly in East Africa, several years apart.  When outbreaks do occur, they kill thousands of cattle.  A livestock vaccine against the disease exists but is rarely used.  It is too expensive for farmers to use routinely, and since it is not effective until a month after vaccination, administering it after an outbreak begins helps very little.  Nevertheless, experts predict that use of the vaccine will increase significantly within the next few years.

Which of the following, if true, provides the strongest justification for the experts’ prediction?

A. Rift Valley fever is spread by mosquitoes, but each outbreak is so widespread that it is impractical to control it by using insecticides.

B. When an outbreak of Rift Valley fever occurs, unaffected countries often refuse to import livestock from the countries affected by the outbreak.

C. It would take less than a month for producers of the vaccine to adjust their production operations to cope with a large increase in demand.

D. Many cattle farmers in East Africa are nomadic or live in remote villages, and such farmers, who have little access to modern veterinary medicine, are particularly hard hit by outbreaks of Rift Valley fever.

E. Recently published research has shown that certain identifiable climatic conditions are almost invariably followed, within two to five months, by an outbreak of Rift Valley fever.

我觉得B比较好，E想不通，希望有牛牛能指点一下，谢谢啦 ；）

 

 

genius_fang

题目是说由于疫苗的价格昂贵以及要1个月才能生效，所以不被广泛采用。但是科学家的判断是接下来几年，疫苗的使用会显著增加~~~然后让你加强：

B说疾病爆发后，未受影响的邻国不进口得病的牲畜，这和题目没有关系啊~~~E说的是在这种疾病爆发之前的3~5个月里，会有一种恒定不变的气候特征，言下之意就是一旦发现这种气候特征，就可以个牲畜打疫苗了，至少这个选项把疫苗生效时间1个月这个不利因素给排除了~加强了结论！！！

faynie

才看到，谢谢 ；）