题目

Boys and girls, please remember ________ your homework here this evening. A. taking         B. to take           C. bringing            D. to bring 答案：D如图，点A1、B1、C1分别是△ABC的三边BC、AC、AB的中点，  点A2、B2、C2分别是△A1B1C1的边B1C1、A1C1、A1B1的中点，依此   类推，则△AnBnCn与△ABC的面积比为    ▲    ．