题目

 ---Do you know what Millie and Andy were doing at 8 o’clock yesterday? ---While Millie_____________ TV, Andy_____________ a book in the bedroom.        A. was watching; was reading               B. watched; read          C. was watching; read                          D. watched; was reading     答案：A如下图所示：要在围墙AB和BC边上插彩旗，要求每两面彩旗之间的距离相等，并且A、B、C处各插一面，这堵围墙最少插几面彩旗？