【单选题】听力原文: It would seem that there are 3 kinds of travel books. The first are those that give a personal description of travels which the author has actually made himself. If they are informative and have...
【简答题】如图, 已知正方形 ABCD , 点 E 在 BC 边上, 将△ DCE 绕某点 G 旋转得到△ CBF , 点 F 恰好在 AB 边上. (1)请画出旋转中心 G (保留画图痕迹) , 并连接 GF , GE ; (2)若正方形的边长为2 a , 当 CE = 时, 当 CE = 时, .