∵AB=CD∠DFC=∠AEB,∠BAC=∠DCA∴△ABE≌△CDF
∵FC=AE,CN=AM∠MAE=∠NCF∴△AME≌△NCF∴∠MEF=∠EFN∴ME‖FN
∵ME=FN∴四边形MENF为平行四边形.