题干
—Does the bookstore math books?
—Yes. Do you want to______ one?
A：sell; buy
B：sell; sell
C：buy; buy
D：buy; sell
答案(点此获取答案解析）
A
—Does the bookstore math books?
—Yes. Do you want to______ one?
A：sell; buy
B：sell; sell
C：buy; buy
D：buy; sell
满足约束条件
，则目标函数
的最大值
与最小值
的比
=" " （ ）