∵直线AB,CD相交于O
∴∠AOB=∠DOC=180°
∵∠BOC=70°
∴∠AOC=180°-∠BOC=110°
∴∠AOD=180°-∠AOC=70°
∵OE平分∠AOC,OF平分∠AOD
∴∠COE=∠AOE=1/2∠AOC=55°
∠DOF=∠AOF=1/2∠AOD=35°