问一道题

qinyitian

Q38:这题选E,可是文中已经说了vaccine against the disease exists but is rarely used,那么即使outbreak马上来，也不见得会很大增加vaccine使用啊？求牛人解答！！！

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?

 

1. Rift Valley fever is spread by mosquitoes, but each outbreak is so widespread that it is impractical to control it by using insecticides.
2. When an outbreak of Rift Valley fever occurs, unaffected countries often refuse to import livestock from the countries affected by the outbreak.
3. 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.
4. 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.
5. 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.

dustyrick

说明了有可能提前2-5个月预测到outbreak of Rift Valley fever, and it only needs one month for the vaccine to kick in. 这样的话, 人们当然会更多的用到这个vaccine.  strong justification !

qinyitian

明白了，谢谢！！

iamwuyan

 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. 是解释A livestock vaccine against the disease exists but is rarely used的原因, 把这句话打破了, 自然就得出答案了