TOEFL Listening: ETS-TOEFL听力机经 - KPUQ3757A05NHHJ9P$

What is the lecture mainly about? A. Ways that ethanol reduces pollution in the United States B. Ways that ethanol production has changed agriculture in the United States C. The advantages and disadvantages of producing ethanol from corn D. Efforts to replace all gasoline used for transportation with corn-based ethanol