题干
—You were out when I dropped by your house.
— Oh, I_________ in Zhongbai Supermarket with my parents.
A：was shopping
B：had shopped
C：am shopping
D：have shopped
答案(点此获取答案解析）
A
为三个盒子中含球最多的盒子里的球数，则 
为（ ）