支气管扩张的早期病理改变是（）。
A.柱状扩张
B.气管扭曲
C.气管坏死
D.气管穿孔
E.空洞形成
参考答案：A
The skirt __________ she spent 50 yuan is very beautiful on her.
A．in which
B．on which
C．for which
D．which
牵引变电所的主要任务是什么？
