独立主格相当于一种描述性状语从句。it+being不难看出，it作形式主语，往往为了引出下一个分句或者其它结构，或者表示天气、时间等。it+being构成的独立主格being不能省略，如：
It hot, we went for swimming.（误）
It being hot, we went for swimming.（正）
天气太热，我们去游泳了。
it being 独立主格结构例句
It being a raining day, we gave up our plan to go hiking.
由于下雨天，我们放弃徒步旅行计划。
It being a Sunday, we had the day off.
因为是星期天，所以我们都休息。
It being Christmas,the government offices were closed.
由于圣诞节的缘故,政府机关都休息.
It being a holiday,all the shops were shut.
由于今天是假日,所有商店都关门了.
It being Sunday, we went to church.
因为是星期天,我们去了做礼拜。
It being Sunday, all the offices are closed.
因为是星期日,所有办公室都关门。
It being Naional Day today,the streets are very crowded.（=As it is National Day today,the streets are very crowded.）
今天是国庆节，街上很拥挤。
It being late, they insisted on leaving right now.
因为天晚了,所以他们坚持马上离开。