题目

 No one is used to_______ at that way, I think.     A. being laughed    B. laugh           C. be laughed         D. laughing 答案：A如图，△ABC是等边三角形，点D、E分别在BC、AC上，BD=CE，AD与BE相交于点F． 1.试说明：△ABD≌△BCE 2.△AEF与△ABE相似吗?请说明理由． 3.试说明：BD2=AD·DF