动脉导管未闭在透视下所见___________是本病的特征性变化。
参考答案:肺门舞蹈征
What are doing here? I ________ for you for ages!
A.have been looked
B.have been looking
C.looked
D.had been looking
在这种急弯道路上行车应交替使用远近光灯。