题目

 It was_______ that they went for a walk in the park. A. such a fine weather                           B. so fine a weather C. such fine weather                            D. so fine weather 答案：C（2011•攀枝花）如图，在等腰梯形ABCD中，AD∥BC，AB=CD=AD，∠B=60°，DE⊥AC于点E，已知该梯形的高为．（1）求证：∠ACD=30°；（2）DE的长度．