It appears作什么成分？

Because our conscious mind is occupied with daily life we don’t always think about the emotional significance of the day’s events —until, it appears, we begin to dream.

讨教各位老师，这里it appears作为插入语，该怎么样理解呢？until we begin to dream, it appears. it appears作主句吗？将it理解为主语，appears理解为vi 出现的意思。

或者将it理解为主语，appears理解为系动词 好像的意思。

it appears 传统语法剖析为插入语。现代语法剖析为评注性状语。为说话人对句子或分句的评论或注解。这里 it appears 意为好像，是说话人讲解好像是如此，给自己留有空间（万一有人有不同怎么看）。