第20题: [单项选择]{{B}}Questions 11 to 18 are based on the conversation you have just heard.{{/B}} A. A chemistry class. B. A biology class. C. A mathematics class. D. A physics class. 参考答案:A 答案解析:[听力原文]
W: The biology class next Monday has been replaced by a chemistry class.
M: Awful. I haven’