<image>One day, Xiaofang went to Teacher Jin’s office to play and accidentally knocked over an ink bottle on the desk, causing the problem on the desk to change to: "As shown in the figure, given that AB⊥BC, (conditions that have been obscured by ink and are thus indiscernible), BC=EC, and CA bisects ∠BCD, try to explain why AC=DC."

1. Based on the available information, can you determine the measure of ∠DEC? If yes, write down the solution process; if not, please explain the reason.
2. Please give Xiaofang an idea to make the original problem complete. The condition you added is ____(only list one).