晚期髋关节结核的X线表现特征是（）
A.股骨头消失
B.病理性后脱位
C.进行性关节间隙变窄
D.边缘型骨质破坏
E.显示肿胀的关节囊
参考答案：A
Miss Li _______ as a secretary for five years in the company, and now she is general manager of it.
A．serves
B．served
C．has served
D．had served
钠冷阱 sodium cold trap
