Analysis: △ ADC △ AEB can be obtained from two angles and a pair of sides, and a conclusion is drawn.

Answer: Proof: In △ADC and △AEB, ∠ B = ∠ C.

∠A=∠A

AE=AD

∴△ADC≌△AEB(AAS)，

∴AB=AC，

∴AB-AD=AC-AE，

∴BD=CE.