平均剥采比是露天采场内剥离物总量与（）的比值。
A.无用矿物量
B.有用矿物总量
C.脉石矿物量
D.矿物量
参考答案：B
"You'll have to wait for two hours, ________ is, at about 11; 30, ________ the medical report will
come out, "the doctor said to me.[ ]
A. that; when
B. which; that
C. that; which
D. it; whose
汽车的发源地是（）。
A、美国
B、日本
C、德国
D、法国
