Some energy experts and environmentalists have expressed skepticism about the benefits of biofuels, especially ethanol produced from corn.

VOA: standard.2009.09.02

The corn to ethanol conversion in the United States, and other things like that has really changed the world landscape in a lot of interesting ways.

在美国,很多类似于玉米制乙醇的技术,正以有趣的方式,改变着我们的世界

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

Corn-based ethanol produces only slightly more energy than it takes to produce it.

VOA: standard.2009.09.02

The bioreactors will grow algae that can produce ethanol fuel through a special process that involves using carbon dioxide from nearby coal-burning power plants to promote faster growth of the algae.

VOA: standard.2009.09.02