[求助]完全看不懂的题目，请指教！GWD16 38

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.

答案选的E， 我是一天头绪都没有！恳请各位相助！

题目说疫苗一个月之后就没用了，但是routinely使用又太贵，所以help little.

E说一种新的研究发现特定的气候条件之后2-5月内就有爆发，说明一定程度上病情可预测，因此有助于避免routinely使用，解决了原来的问题

1.疫苗接种一个月后才能有效  2.疫情爆发之后使用，效果不理想。

提前预测疫情发生，就可以提前接种。

可是，题目中专家是对next few years的预测啊？

我也不懂。请高手详细解答。

谢谢！