只有（）有权进行调度操作改变设备运行状态。
A.调度主任
B.实习调度员
C.正值调度员
D.副值调度员
参考答案：C, D
Mother asked the youngest kid _______with his toy car．
A．what the matter was
B．what was the matter
C．what the matter is
D．what is the matter
采煤工作面任意丢失顶煤和底煤会出现哪些不利影响？
