求助: GWD 9-12

问道关于我兄弟的问题:

GWD-9-Q12:

A mosquito bite can transmit to a person the parasite that causes malaria, and the use of mosquito nets over children’s beds can significantly reduce the incidence of malarial infection for children in areas where malaria is common. Yet public health officials are reluctant to recommend the use of mosquito nets over children’s beds in such areas.

Which of the following, if true, would provide the strongest grounds for the public health officials’ reluctance?

A.    Early exposure to malaria increases the body’s resistance to it and results in a lesser likelihood of severe life-threatening episodes of malaria.

B.    Mosquito bites can transmit to people diseases other than malaria.

C.    Mosquito nets provide protection from some insect pests other than mosquitoes.

D.    Although there are vaccines available for many childhood diseases, no vaccine has been developed that is effective against malaria.

E.     The pesticides that are most effective against mosquitoes in regions where malaria is common have significant detrimental effects on human health.

答案给的是A,我觉得A存在一种前提是这些孩子之前感染过malaria, 但文中貌似得不出这个信息，万一children玉体从未被蚊子光顾过，那挂蚊帐岂不是就有效了？相比之下，我觉得虽然C很滑稽，但更正确一点。请NN指教~

不知我的理解对不对：

官员说的是不推荐用蚊帐，题目要求解释为什么不挂蚊帐。

A如果是您说的 “不给挂蚊帐，小孩就会感染m”，那就应该挂蚊帐，这削弱了官员的说法呀……

A:小時候如果感染M的話抗體反而會增強, 患上由M引發的重病的機會就會降低, 也就是說小朋友感染M也不至於危害性命, 但是小時候受保護不感染以後還有機會感染,因為malaria is common, 那時候患重病而死的機會就大大增加了.

換個說法,不掛蚊帳患重病的機率假設是20%,掛了死亡率是80%,所以官員不支持.

thanks a lot!

i got it~