（1）∵CB∥OA,∠C=∠OAB=120°,∴∠COA=180°-∠C=180°-120°=60°,∵CB∥OA,∴∠FBO=∠AOB,又∵∠FOB=∠AOB,∴∠FBO=∠FOB,∴OB平分∠AOC,又∵OE平分∠COF,∴∠EOB=∠EOF+∠FOB= ∠COA= ×60°=30°；（2）不变,...