[解析]
(1)C.推理判断题。根据文中The findings raised the possibility that reducing pollution might lead to a drop in diabetes cases." (这些发现提高了减少污染可能会导致糖尿病病例的下降的可能性。) 可知,污染和糖尿病例是有着一定关系的,所以A项Diabetes had lttle to do with outdoor air pollution. (糖尿病与户外空气污染没关系。) 错误;同时B项Reducing pollution might lead to a lot of diabetes cases. (减少污染也会导致大量的糖尿病病例。) 与原文文意不符,所以错误。又根据文中"Our research shows a significant link between air pollution and diabetes globally." (我们的研究表明空气污染与全球糖尿病有着重要关系。) 可知C项Air pollution contributed significantly to diabetes globally. (空气污染对全球糖尿病发病有重要影响。) 正确;根据文中"even at low levels of air pollution currently considered safe by the US Environmental Protection Agency (EPA) and the World Health Organization (WHO)." (即使是EPA和WHO组织现阶段认为的安全的低水平的空气污染。)可知D项Low﹣level air pollution was always considered safe by WHO. (低水平污染总是被WHO认为是安全的,与文章不符,文章中只是说现在,所以D项错误。故选C项。
(2)B.细节理解题。根据文中"To evaluate outdoor air pollution,the researchers looked at small pieces of dust,smoke and liquid droplets." (为了评估室外空气污染,研究者观察了小块的灰土,烟和液体飞沫。) 可知,研究者评估空气污染是通过分析空气气中的小物质,故选B项。
(3)B.写作目的题。根据第五段数据展示In the US,the EPA's pollution limit was 12 micrograms per cubic meter of air,the highest level of air pollution considered safe for the public,as was set by the Clean Air Act of 1990 .美国1990设定的污染限制到2012再次将污染限制更新后,已经是美国公认的安全了,但是通过Al﹣Aly的团队的发现,将患糖尿病的风险设定为每立方米空气2.4微克,但是后来在每立方米空气污染水平为5至10微克的公民样本中,约有21%患上了糖尿病。所以根据第五段数据展示,作者是想要证明第四段最后一句话"The US experienced a middle risk of pollution﹣related diabetes." (美国经历了污染引起糖尿病的中度风险。) 的这个观点,故选B项。