“独立主格结构”实质相当于带有自己主语的非限定状语从句，定语从句或者并列句。但独立主格结构是一个短语结构，在句中有多种作用。如：表原因、表条件、表方式、表伴随、表时间等，在句中通常起状语，定语和补语的作用。
A.作状语
独立主格结构作状语，其功能相当于一个状语从句或并列分句。
1.表示时间
例如：Class over, we began to play basketball.
相当于Class was over, we began to play basketball.All the guests seated, they began their dinner.
解析：名词+副词;表时间。
2.表示原因
例如：There being nothing else to do, they gone away.相当于Because there was nothing else to do, they gone away.
解析：代词+-ing; 表原因。
3.表示条件All the homework done, you can have a rest.相当于As long as all the homework is done, you can have a rest.解析：名词+过去分词；表条件。
4.表示伴随情况
例如：Almost all metals are good conductors, gold being the best of all.
【解析】gold being the best of all相当于and gold is the best of all。
5.表示补充说明
例如：The workers redoubled their efforts, each man working like two.工人们加倍努力，一个人干两个人的活。
【解析】each man working like two相当于that is to say, each man worked like two。
B.作定语
独立主格结构作定语，其功能相当于一个定语从句。
例如：Tom was walking along the road without any street lights on its both sides.(without的复合结构作定语,修饰the road )
相当于Tom was walking along the road that didn’t have any street lights on its both sides.
解析： without的复合结构作定语,修饰the road .
注意：独立主格有时相当于并列句。
例如：She is broken-heart, for tears are on her powered cheeks.寸寸柔肠，盈盈粉泪。
相当于：She is broken-heart, tears on her powered cheeks.
或者She is broken-heart, with tears on her powered cheeks.
