网友质疑有道理以下几个句子都是正确的

【1】There being no buses, we had to walk there.【独立主格结构】

备注：There being no buses为独立主格结构作原因状语。
【2】Because/As/Since there were no buses, we had to walk there.【原因状语从句】

备注：Because/As/Since ,为从属连词引导原因状语。
【3】There were no buses, so we had to walk there.【so引导并列句结构】
备注：并列连词so引导并列句。