一、含义：
分词作状语时，自带逻辑主语（与主句逻辑主语不同）
独立主格结构是由名词或代词作为逻辑主语，后跟形容词、副词、介词、短语、分词、不定式等构成的独立结构。本身不是句子，在句中作状语。
二、特点：
①主格结构一般用逗号隔开，不能使用任何连接词。
②独立主格结构的逻辑主语与句子的主语不同，它独立存在。
③名词或代词与后面的形容词，副词，介词，短语，分词，不定式等存在逻辑上的主谓关系或被动关系。
三、主要形式
1.逻辑主语+非谓语动词
①名词或代词+现在分词(doing):（动词和逻辑主语是主谓关系，表示主动或正在进行的动作）
She ran up to me ，her hair flying in the wind.(hair和fly是主动关系，方式状语)
②名词或代词+过去分词（done):(动词和逻辑主语是动宾关系或系表结构，表示被动或已完成的动作)
This done， we went home.(被动完成，时间状语)
③名词或代词+不定式(to do):( 词语不定式构成逻辑上的主谓关系，表示将要发生的动作)
We divided the work，he to clean the window and I to sweep the floor.（表主动将来）
2.逻辑主语+形容词/副词,介词短语
①名词或代词+adj/adv:(形容词或副词常用来说明名词或代词的性质、特征或所处的状态)
He sat in the front row， his mouth half open.(形容嘴巴张着的状态，方式状语)
Summer over ，the students returned to school.(时间状语)
②名词或代词+介词短语:(介词短语也用来说明名词或代词的性质特征和所处的状态该结构中一般不用形容词性物主代词和冠词)
He entered the classroom， book in hand.(方式状语，book前不能加冠词)
3.with复合结构(方式状语)
①With+宾语+形容词
The children were listening to the teacher with their eyes wide open.
②With+宾语+介词短语
The old man used to take a walk with a stick in his hand.
③With+宾语+副词
the girl walked away with her head up.
④With+宾语+现在分词
Mary felt very shy with so many eyes looking at her.(主动)
⑤With+宾语+过去分词
If you sit looking away from a person， or with your back turned ，you are saying you are not interested in that person.(back和turn之间是动宾关系)
⑥With+宾语+不定式
With too much work to do the next day ，he felt anxious and didn't sleep well.（表将来）
注意：名词或代词+介词短语（既无形容词性物主代词，也无冠词）和with+宾语+介词短语（既有形容词性物主代词，也有冠词）
Miss smith entered the classroom， book in hand.
Mr smith entered the classroom with a book in his hand.
4.There being+名词/代词(原因状语)
There being no bus, we had to walk there.
There being nothing to do, we went home.
It being+名词/代词(原因状语)
It being a holiday ，all the shops were shut.=Because it was a holiday， all the shops were shut.
四、用法
①作时间状语
The work done， we went home.
②作条件状语
Whether permitting ，they will go on an outing to the beach tomorrow.
③作原因状语
An important lecture to be given tomorrow ，the professor has to stay up late into the night.
④作伴随状语
He was lying on the grass ,his hands crossed under his head.
⑤作补充说明
A hunter came in， his face red with cold.
