C28.B.根据“as consequence of cost benefits of improved health outcomes可确定答案。29.B.根据“Air pollution caused by emissions(排放物) from power plants is known to cause respiratory(呼吸道 discascs."、"In short, cleancr air would save475 human lives cach year in the United Stat可确定答案30.C根据第4、5段中划线部分,可知研究人员在研究中是通过计算获取各种数据出“省电就是拯救生命”的结论。 Abel and his colleagues uscd suite of hrce widely used modcls to calculate power plant emissions, air quality and human deaths over three summer months when energy use is high. Their findings show that 12 percent increase in summertime energy ficiency would reduce exposure to air pollution. In short, cleaner air would save 475 human lives each year in the United States, worth an estimated 4 billion. That savings translates to almost 5 cents per kilowatt hour of energy used. That is particularly significant, the UW team notes. given that electricity costs about 10 cents per kilowatt hour on average.31.D。概括最后一段内容可确定答