小安阅读材料的53篇，小儿麻痹症~~求大牛指点~~~

zhima427

Although genetic mutations in bacteria and viruses can lead to epidemics, some epidemics are caused by bacteria and viruses that have undergone no significant genetic change. In analyzing the latter, scientists have discovered the importance of social and ecological factors to epidemics. Poliomyelitis (poliomyelitis: n.小儿麻痹症, 急性骨髓灰白质炎), for example, emerged as an epidemic in the United States in the twentieth century; by then (by then: 到那时候), modern sanitation was able to delay exposure to polio (POLIOMYELITIS)until adolescence or adulthood, at which time polio infection produced paralysis. Previously, infection had occurred during infancy, when it typically provided lifelong immunity without paralysis. Thus, the hygiene that helped prevent typhoid epidemics indirectly fostered a paralytic polio epidemic. Another example is Lyme disease, which is caused by bacteria that are transmitted by deer ticks. It occurred only sporadically during the late nineteenth century but has recently become prevalent in parts of the United States, largely due to an increase in the deer population that occurred simultaneously with the growth of the suburbs and increased outdoor recreational activities in the deer’s habitat. Similarly, an outbreak of dengue hemorrhagic fever became an epidemic in Asia in the 1950’s because of ecological changes that caused Aedes aegypti, the mosquito that transmits the dengue virus, to proliferate. The stage is now set in the United States for a dengue epidemic because of the inadvertent introduction and wide dissemination of another mosquito, Aedesalbopictus.

1.The passage suggests that a lack of modern sanitation would make which of the following most likely to occur?

(A) An outbreak of Lyme disease

(B) An outbreak of dengue hemorrhagic fever

(C) An epidemic of typhoid

(D) An epidemic of paralytic polio among infants（C）

(E) An epidemic of paralytic polio among adolescents and adults
请问这一题为什么不选D而选C呢？？？

wsmgr

Thus, the hygiene that helped prevent typhoid epidemics indirectly fostered a paralytic polio epidemic。
搞卫生反而会间接促进polio的流行

zhima427

Thus, the hygiene that helped prevent typhoid epidemics indirectly fostered a paralytic polio epidemic。
搞卫生反而会间接促进polio的流行

-- by 会员 wsmgr (2012/7/7 11:32:35)

谢谢~~但是hygiene和modern sanitation一样吗，特别是在不清楚词义的时候，而且，怎么判断这个是most likely呢？？真心纠结啊~~~~

潮落时分

Previously, infection had occurred during infancy, when it typically provided lifelong immunity without paralysis.原文这句话说明了：在以前没有现代卫生的时候，幼儿时期感染 骨髓灰质炎可以产生一生的免疫，不会得麻痹症。
(D) An epidemic of paralytic polio among infants
D选项的意思是：没有现代卫生，在幼儿中会流行骨髓灰质炎导致的麻痹症。改变了原文意思

sxhmzxy

还是阅读能力是王道啊

eliane小小爱

觉得XA81篇好难啊

xiaozher

这个polio infection 在不同时期会引起不同的病。它在infant时期引起typhoid，同时产生对paralytic的终生免疫；在adolescence or adulthood时期引起paralytic。而现代卫生技术延迟了人们感染polio的时间，所以结果是人们不会得typhoid病，但会得paralytic的病。 下面说的就是这个意思。
modern sanitation was able to delay exposure to polio until
adolescenceor adulthood, at which time polio
     infection produced paralysis. Previously, infection
     had occurred during infancy, when it typically
     provided lifelong immunity without paralysis. Thus,
     the hygiene that helped prevent typhoid epidemics
indirectly fostered a paralytic polio epidemic.
因此如果没有现代卫生，就会有很多typhoid病。 D项说婴儿时期的paralytic polio病，本身就是不对的，因为婴儿时期即使感染polio，也不会paralytic，而是typhoid。