与商品储存量多少有直接关系的是（）.
A．订货处理成本
B．存货维持成本
C．采购成本
D．缺货成本
参考答案：B
______ is surprising to us is that Tom, for ______ English was once boring, can speak English fluently as though he were a native speaker.
A．What; whose
B．What; whom
C．It; whose
D．As; whom
神经-肌肉接头处传递信息的化学物质是（）
A.肾上腺素
B.去甲肾上腺素
C.γ-氨基丁酸
D.乙酰胆碱
E.5-羟色胺
