下列情况不会造成室内空气污染的是 [ ]
A.吸烟产生一氧化碳、尼古丁等物质
B.水烧开时产生大量水蒸气
C.装修木板释放出甲醛、苯等物质
D.大理石释放出放射性气体--氡
答案:B
He went out to play football, leaving his homework _________.
A.to unfinish
B.to be unfinished
C.unfinishing
D.unfinished
接触网中间支柱折断事故抢修方法有哪些?