[解析]
(1)D.细节理解题。根据第一段的Improved air quality to reduce ozone (臭氧) pollution may have avoided the loss of 1.5 billion birds during the past 40 years,a study found.That's nearly 20% of bird life in the United States today.一项研究发现,为减少臭氧污染而改善空气质量可能在过去40年里避免了15亿只鸟类的损失。这几乎占到了今天美国鸟类生命的20%。可知,现在美国的鸟的数量是15亿厨艺20%,即75亿。故选D。
(2)A.细节理解题。根据第三段的The findings suggest that ozone pollution is most harmful to the small birds—such as sparrows,warblers and finches—that make up 86% of all North American land﹣bird species.Ozone pollution directly harms birds by damaging their breathing systems,and indirectly harms their food sources.研究结果表明,臭氧污染对麻雀、莺和雀鸟等小型鸟类的危害最大,这些鸟类占北美陆地鸟类的86%。臭氧污染通过破坏鸟类的呼吸系统,并间接损害它们的食物来源。可知,调查结果是臭氧污染间接危害鸟类的食物来源。故选A。
(3)B.情感态度题。根据倒数第二段的The good news here is that environmental policies intended to protect human health and return important benefits to birds too.好消息是,环境政策旨在保护人类健康,并将重要的利益回报给鸟类。可知,Amanda Rodewald对鸟类在美国的未来持的态度是积极的。故选B。
(4)C.标题判断题。通读全文,尤其是第一段的Improved air quality to reduce ozone (臭氧) pollution may have avoided the loss of 1.5 billion birds during the past 40 years,a study found.一项研究发现,为减少臭氧污染而改善空气质量可能在过去40年里避免了15亿只鸟类的损失。可知,本文主要讲的是一项发明,为减少臭氧污染而改善的空气质量可能在过去40年里避免了15亿只鸟类的损失。由此可知,本文的最佳标题是:减少臭氧污染可能避免了鸟类的死亡。结合选项:A.Ground﹣Level Ozone Makes up Most of the Air We Breathe地面臭氧构成了我们呼吸的大部分空气;B.Environmental Policies Intend to Protect Human Health旨在保护人类健康的环境政策;C.Reduced Ozone Pollution May Have Avoided Bird Deaths减少臭氧污染可能避免了鸟类死亡;D.Regulations Bring Important Protection Benefits to Birds法规为鸟类带来重要的保护效益。故选C。