题目

 —Are you sure you can do well in today’s test, Lucy?    —         . I’ve got everything ready. A. It’s hard to say                     B. I’m afraid not C. I think so                               D. I hope not 答案：C如图，DE⊥AB于E，DF⊥AC于F，若BD=CD、BE=CF．（1）求证：AD平分∠BAC；（2）直接写出AB+AC与AE之间的等量关系．