∠BOD的余角是∠BOE，∠COE的补角是∠DOE，∠AOC的补角是∠BOC.
1........∠COB,∠AOD2........∠DOE3........∠COB,∠AOD
∠BOE∠DOE∠BOC
1_∠BOE 2_∠DOE 3_∠BOC
∠BOE ∠DOE ∠BOC
