如图所示,已知:DE∥BC,DF、BE分别平分∠ADE和∠ABC,试说明∠FDE=∠DEB. 解:∵DE∥BC _________ ,∴∠ADE=_________,∵DF、BE分别平分∠ADE和∠ABC(已知),∴∠ADF=_________,∠ABE=_________,∴∠ADF=∠ABE,∴ _________ ∥ _________ ,∴∠FDE=_________.