2013gre考试预测：4月gre阅读备考机经（13）
新gre考试阅读机经：乙醇汽油 乙醇汽油 Although, recent years have seen substantial reductions in noxious pollutants from individual motor vehicles, the number of such vehicles has been steadily increasing consequently,more than 100 cities in the United States still have levels of carbon monoxide, particulate matter, and ozone (generated by photochemical reactions with hydrocarbons from vehicle exhaust) that exceed legally established limits. There is a growing realization that the only effective way to achieve further reductions in vehicle emissions—sho... [ 查看全文 ]2013gre考试预测：4月gre阅读备考机经（13）的相关文章
