OG-11,verbal review,RC第6题，各位大侠帮忙

该题的正确选项为c,我没有看懂给出的解释，如果选c，那么就意味着modern sanitation=hygiene, polio=typhoid epidemic,可是从上下文关系我无法得出上述结论，望各位大牛帮忙。

这题63篇里有，我不记得是那篇了。书不在手边，不过记得这题，当时我也错了。这段确实挺绕人的。我记得应该再往下面看一句，就能懂了，它需要一个推理。你去讨论总汇搜一下吧

the original sentence in the passage is "the hygiene that helped prevent typoid epidemics indirectly fostered a paralytic polio epidemic". This sentence tell us that the hygiene can help prevent typoid epidemics.So we can conclude that if there is a lack of hygience will lead to typoid epidemics.So the answer is C.

Up is my understanding.

but my problem is i could not see any connection b/w modern sanitation with hygiene, and the connection b/w polio and typoid epidemics. would you pls tell me how do u get the equation above, thank you very much for yr reply.