题目

Could you please tell me         get to the railway station?  A. where can I    B. how can I     C. where I can   D. how I can 答案：D如图，点P是正方形ABCD的对角线BD上一点，PE⊥BC于点E，PF⊥CD于点F，连接EF．给出下列五个结论：①AP=EF；②AP⊥EF； ③△APD一定是等腰三角形； ④∠PFE=∠BAP；⑤PD=EC．其中正确结论的序号是    ．