政策文件注重（）的要求。
A.导向性
B.规范性
C.原则性
D.确定性
参考答案：A, C
Although there are no classes in the afternoon now, no student ______ go out of school without
the head teacher's permission. [ ]
A. will
B. must
C. may
D. shall
（）是库存管理的核心内容。
