变电站的应急照明可采用蓄电池作备用电源，其连续供电时间不应少于30min。
参考答案：错
如果一个数的相反数是最小正整数，则这个数是______．
Father asked Edison ________ doing that for. [ ]
A. how is he
B. what he was
C. why was he
D. where he is
