加油加气站的变配电间或室外变压器应布置在爆炸危险区域之外,且与爆炸危险区域边界线的距离不应小于()。
A.3m
B.4.5m
C.6m
D.7.5m
参考答案:A
解析:
We read the newspaper ____________ suddenly the light went out. [ ]
A. when
B. while
C. before
D. after