问题
单项选择题
Why does the author mention fresh coffee in Paragraph 2
A．As an example of complex substances having not been duplicated satisfactorily.
B．Because the coffee fragrance is hard to produce.
C．To conclude the passage.
D．The smell of fresh coffee is inviting.
答案
参考答案：A
解析：[分析] 推断题型。 见上题推理：作者之所以提及新鲜咖啡，是借此例来说明一些成分复杂的物质很难令人满意地合成出来。所以选项A为答案。