生产成本是指（）。
A、生产一吨烧结矿所需的费用
B、每月生产烧结矿所需的费用
C、每天生产烧结矿所需的烧结费用
参考答案：A
He became the ________ of criticism by the readers for his newlypublished book.
A．target
B．theme
C．fortune
D．figure
如何确定金刚石钻头上金刚石的分布与排列？
