筛骨最常见的骨折部位是（）
A.筛骨垂直板
B.筛骨外侧壁
C.筛窦内侧壁
D.筛窦前组骨壁
E.筛窦后组骨壁
参考答案：B
---Excuse me. I’m looking for Be the Best of Yourself.
---Sorry. The book you ask for ______ out.
A．is selling
B．is sold
C．was selling
D．will be sold
扩展名为WAV的文件属于（）文件格式。
A.视频
B.矢量图形
C.动画
D.音频
