装置停工检修安全工作内容是（）。
A、消防器材完好
B、防毒面具齐全
C、装置吹扫干净
D、A、B和C
参考答案：D
已知圆C：（x-a）2+（y-2a）2=1（a∈R），则下列一定经过圆心的直线方程为（ ）
A．x+2y=0
B．2x+y=0
C．x-2y=0
D．2x-y=0
—Excuse me,could you tell me ?
—At two o'clock tomorrow afternoon. [ ]
A. when we will have a class meeting
B. when will we have a class meeting
C. where we will have a class meeting
D. where will we have a class meeting
