题目

 Fear is something that you are born with. You can’t ______yourself of it completely but you can ____ certain fears under certain conditions. . A. get; overcome      B. rid; overcome      C. overcome; rid of    D. break; get rid of  答案：B函数f（x）=-x2+8x-14在区间[2，5]上的零点个数是（　　）A．0个B．1个C．2个D．无数个