题目

I’ve already         there a couple of times, but I’m happy                    again. A. been to, going       B. been, to go     C. went, to go 答案：B如图，AB是圆O的直径，P是圆弧AB上的点，M，N是直径AB上关于O对称的两点，且AB=6，MN=4，则•等于    ．