Being a public holiday,?nobody was in the office.以上句子为现在分词作原因状语,逻辑主语it指代时间,如果把逻辑主语it加上就构成独立主格结构作原因状语。备注:逻辑主语为it的情况下,现在分词逻辑主语可以不是后面句子主语。所以网友给出英语句子是正确英语句子。It being a public holiday,?nobody was in the office.备注:以上为代词(it)+现在分词构(being a public holiday)成独立主格结构作原因状语。