题目

With the incomes (rise) continuously, some people now can afford expensive clothing of the fastest fashion. 答案：【1】rising设函数f（x）=x3-4x+a，0＜a＜2．若f（x）的三个零点为x1，x2，x3，且x1＜x2＜x3，则（ ）A．x1＞-1B．x2＜0C．x2＞0D．x3＞2