题目

－ You haven’t been to the West Lake in Hangzhou, have you?   －______. How I wish to go there!   A. Yes, I have      B. Yes, I haven’t   C. No, I have      D. No, I haven’t 答案：D若方程|x2-6x+8|=x+a有三个根，则a的值为（ ）A．-2B．C．-2或D．不存在