定量库存控制是指库存量下降到（）时，按固定的订购数量进行订购的方式。
A.订购点
B.订购批量
C.安全库存量
D.最低库存量
参考答案：A
She'll never forget her stay there ________ she found her son who had gone missing two years before.[ ]
A．that
B．which
C．where
D．when
