阅读理解，根据短文选择正确的一项
One day a policeman was walking in the park. He saw a man there. The man was holding a penguin（领着一个企鹅）. The man said to the policeman, “ I found this penguin this morning. What shall I do with it?”“Take it to the zoo,” said the policeman. The next day the policeman saw the man again. He was still holding the penguin. The policeman said, “Why didn't you take the penguin to the zoo?”“I did,” said the man. “I took him to the zoo yesterday. Today I'm taking him to the cinema.
如图，在△ABC中，D是BC边上一点，E是AD的中点，过A作BC的平行线交CE的延长线F，且AF=BD，连结BF．
（1）求证：BD=CD；
（2）如果AB=AC，试判断四边形AFBD的形状，并证明你的结论；
（3）当△ABC满足什么条件时，四边形AFBD为正方形？（写出条件即可，不要求证明）
配平下列方程式：（系数为1的不用填写）
①____ C2H6+____ O2____ CO2+____ H2O
②____ Fe3O4+____ Al____ Fe+____ Al2O3
③____ Al+____ H2SO4=____ Al2（SO4）3+____ H2
④____ NaOH+____ H2SO4=____ Na2SO4+____ H2O．
若数据1、﹣2、3、x的平均数为2，则x=____．
____ CO2+____ H2O
____ Fe+____ Al2O3
