美国环保署周二提议，在未来两年内让规模较大的炼油厂掺混更多生物燃料，此举意在11月国会选举前争取农业州选民的支持。
The U.S. Environmental Protection Agency on Tuesday proposed to make larger refiners blend more biofuels over the next two years, seeking to appeal to farm-state voters ahead of November's congressional elections.