BE=CF.
[证明]
∵∠DAE=∠DAF、DE⊥AE、DF⊥AF,∴DE=DF.
∵DG⊥BC、BG=CG,∴BD=CD.
∵DE=DF、BD=CD、∠BED=∠CFD=90°,∴Rt△BDE≌Rt△CDF,∴BE=CF.