变更计划主要指变更（）及取送作业的区域或线路。
A.上下车位置
B.辆数
C.作业方法
D.股道
参考答案：B, C, D
_____ many times, but he still doesn’t know how to operate the machine properly.
A．Although I have shown him
B．I have shown him
C．Having been shown
D．Having shown
利率的换算公司=（）.
A.年利率/12=月利率
B.月利率/30=日利率
C.年利率/360=日利率
D.年利率=月利率X12=日利率X360
