BE=DF,BE∥DF
证明:
∵AE=AF+EF,CF=CE+EF,AF=CE
∴AE=CF
∵AB∥CD
∴∠A=∠C
∵∠B=∠D
∴△ABE≌△CDF (AAS)
∴BE=DF,∠AEB=∠CFD
∴BE∥DF