（）不能实行运价下浮。
A.金属矿石
B.矿物性建筑材料
C.棉花
D.水泥
参考答案：C
He has spent ____ money on his new house.
A．lot of
B．a great deal of
C．a great many
D．a large number of
电力系统负荷预测分为系统负荷预测和（）预测两大类。
