A. they are much more economic B. they can produce only one cup C. they are more convenient and easier to operate D. they are more economical 参考答案:D 答案解析:[试题分析] 细节题。通过题于回到文章中相应的位置可知答案。 [详细解答] 见文章第二段第三句:Since many people make a pot of coffee in the mor