下列哪项不是硅肺的基本病理变化
A.硅结节
B.弥漫性肺纤维化
C.硅肺性空洞
D.胸膜增厚
E.大量纤维蛋白渗出
参考答案:E
I think the MP3 is very helpful. It ____ for listening to music. [ ]
A. is used
B. uses
C. was used
D. used
Visual FoxPro的核心是 【18】 。