题目

函数f(x)=-在区间(-∞,- )上是(    ) A.增函数                                 B.减函数C.有时增有时减                        D.无法断定其单调性 答案：AExcuse me，but may I ask you         ? A．what business are you in                             B．what business you’re in C．in what business are you                             D．are you in what business