证明：过点C，作CG平行EF,D是中点，BD=CD,∠BDE=∠CDF,∠B=∠CGD,△BED≌CGD,，BE=CG,,，BE=CF,所以CG=CF.所以∠F=∠CGF,由CG平行EF,所以，∠AEF=∠CGF所以AE=AF
