中国传统建筑中官式建筑的最大特点是（）
A.追求雄伟壮丽
B.追求淡雅含蓄
C.追求实用性
D.追求神秘性
参考答案：A
______ he was exercising at the park yesterday morning, he found a purse under the tree.
A. While B. Before C. Though
若（3x-1）n（n∈N*）的展开式中各项系数之和为128，求展开式中x2的系数-189______．
