关于原因状语从句的题目

问题描述:

关于原因状语从句的题目
________(Be Sunday,It being Sunday),the supermarket was closed.
请问,这题该怎么分析的?

用It being Sunday
没连词,有逗号,是独立主格
因为是星期天,所以超市不营业
because it is sunday,the supermarket was closed.