D型电控发动机对空气的计量是()。
A.直接计量;
B.间接计量;
C.混合计量;
D.不计量
参考答案:B
I have had my radio_____, and do you have any radios _____in the same shop?[ ]
A. repair, to repair
B. repaired, to be repaired
C. repaired, repair
D. to repair, repairing
盈亏平衡点的产品销量等于固定成本费用与()之比。