矿井按规定及时（）。
A.清理水仓、水沟
B.保证排水畅通
C.检查通风机
D.检查机电设备
参考答案：A, B
A total of 264,302 people in the country were reported __________ with HIV by the end of last September.
A．to have been infected
B．to be infected
C．to having been infected
D．to have infected
磨煤机跳闸功能试验时，选项（）不会引起磨煤机跳闸。
A.磨煤机层电源故障延时达到设定值
B.磨煤机密封风差压高延时达到设定值
C.磨煤机冷风门未开
D.煤仓煤位低-低信号发出
