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标题: GWD-12-Q38请教 [打印本页]

作者: hulala86 时间: 2008-8-29 23:25
标题: GWD-12-Q38请教

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
        游牧的; 流浪的
            or live in remote villages, and such farmers, who have little access to modern veterinary
        兽医的
            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.

我选的是A，觉得是不是排除他因的支持的，既然不能捕蚊子防止fever，那就只能打疫苗了。可是选E我总不明白，答案说：

E说那种病之前的2-5个月的天气条件几乎不变，就是说在这种病来之前的2-5月就可知道这种病即将爆发，然后就能用疫苗要support专家的观点

天气不变并不能保证一定就会发病啊。。。。。。。

E说那种病之前的2-5个月的天气条件几乎不变，就是说在这种病来之前的2-5月就可知道这种病即将爆发，然后就能用疫苗要support专家的观点

天气不变并不能保证一定就会发病啊。。。。。。。

作者: dianecarton 时间: 2008-8-30 06:38

恩

[此贴子已经被作者于2008-9-11 23:15:16编辑过]

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