当道路表面有积雪时，可播撒（）等进行融雪。
A.工业盐
B.煤渣
C.锯末
参考答案：A, B
As an operating system repeatedly allocates and frees storage space, many physically separated unused areas appear. This phenomenon is called （）.
A．fragmentation
B．compaction
C．swapping
D．paging
在医学服务中如何体现公正原则？
