lOkV～35kV小电流接地系统发生单相接地的线路，其最长允许运行时间原则上不得超过（）h。
A、1
B、2
C、5
D、6
参考答案：B
After the discussion, the students asked their teacher _______ next. [ ]
A. what to do
B. where to do
C. how to do
D. which to do
