参考答案

正确答案：C
解析：该题问：本文暗示了以下哪一项所表述的内容?由第二段第二行．．．because science had yet to suggest a plausible biological mechanism by which breathing low concentrations of urban dust might sicken or kil people中的yet隐含有“科学尚未找到一种合理的生物学机理……”可知，选项C与其一致，应为正确答案。由第二段第一行 many industrialists argued that they shouldn't have to pay for better pollution control可知，选项A的many industrialists feel no concern for the improvement of pollution control(很多企业家对提高控制污染的水平漠不关心)不正确；由第二段第二行breathing low concentrations of urban dust might sicken or kill people可知，选项B的breathing low concentrations of urban dust does not necessarily sicken or kill people(呼吸灰尘含量低的城市空气不一定危害人)不正确；由第一段中的Now，scientists．．．describe how they uncovered what they think may be one of the basic elements of the toxicity可知，选项D的scientists have done nothing to reveal the mystery of the toxicity of low concentration of urban dust(科学家没有做任何事去揭示低灰尘含量的城市空气有毒性的奥秘)不正确。