第28题: [单项选择]Questions 23 to 25 are based on the conversation you have just heard.A. A new fuel for buses. B. The causes of air pollution. C. A way to improve fuel efficiency in buses. D. Careers in environmental engineering. 参考答案:C 答案解析:[解析] 23-25 M: Hi Diana, mind if I sit down W: Not at all, Jerry. How have you been M: Goo