题目

When I got to the classroom just now. I found that Tom ______on a math problem. A) worked            B) works            C) will work        D) was working 答案：D8．苏宁电器打算销售电视机480台．第一天卖出160台，第二天又卖出剩下的$\frac{9}{16}$．第一天比第二天少卖出多少台？