题目

选择合适的句子完成对话。A. Let's go to the shop.B. Which one do you want?C. Which ones do you want?D. My school bag is too old.E. This one is too small.A: Mum, I want a new school bag. B: All right. A: This shop has some schoolbags. B: I want that one. That one is big.A: Well. Let's buy the big one. 答案：【1】D【2】A【3】B【4】E已知方程a2x2+（a+2）y2+2ax+a=0表示的曲线是圆，则实数a的值是-1-1．