氧气的化学性质下面（）是错误的。
A、化学性质特别活泼B
暂无解析
Thosewho’dliketovisittheexhibition________(sign)yournameshere.
I'msorryIforgottowrite;Ihadsomuchelse________mymind.
SinceWilliamhadbeenseriouslyillforseveralmonths,hisparentswereworriedabout________toreturntoschoolfull-time.
将一枚硬币重复掷n次,以X和Y分别表示正面向上和反面向上の次数,则X和Yの相关系数等于（）
Whenworkersareorganizedintradeunions,employersfindithardtolaythem________.
