∵AB=CD,AE=DE.BE=CE
∴⊿AEB≌⊿DEC
∴∠AEB=∠DEC
∵AE=DE
∴∠EAD=∠EDA
又∠AED+∠EAD+∠EDA=180°
∠AEB+∠AED+∠DEC=180°
∴∠DAE=∠AEB
∴AD∥BC