独立主格结构指带主语的动词分词、介词、或副词词组。 何谓独立主格结构? 它是指与主语之间无任何语法关系的名词或代词加上一个分词的结构。它不修饰单个的词，而修饰整个句子。
2) 提供主句中重点部分的相关细节。 例 Freud distinguished three kinds of anxiety, each arising from a different source of perceived danger. "each" 是独立主格结构，"arising from"是动词短语。注意这个独立主格结构是一个"干巴巴"的句子。通过改变动词形式，它的面貌可焕然一新：Each arises from a different source of perceived danger.
再看以下例句 Before: His nose was running and his hands were shaking. He left the theater like that. Interesting: His nose running and his hands shaking, he left the theater.
Before: He is known for his bad temper, so I fear the encounter. Interesting: I fear the encounter, his temper being what it is.
Plain: If the weather is favorable tomorrow, we will spend the entire day climbing Huang Shan.
Good: Weather permitting, we will spend the entire day tomorrow climbing Huang Shan.
Plain: Let’s pray that the Southeast Asian economy will soon return to normal.
Good: The Southeast Asian economy, God willing, will soon return to normal.
Plain: Early radio reports exaggerated the success of the raid on the Embassy. Some even indicated that the Vietcong had occupied several floors of the building. Better: Early radio reports exaggerated the success of the raid on the Embassy, some even indicating that the Vietcong had occupied several floors of the building.
Plain: Even though the drug controversy was still festering around him, in the end, defending Australian Open champion Petr Korda walked away with a salute to a cheering crowd. Better: In the end, defending Australian Open champion Petr Korda, the drug controversy around him still festering, walked away with a salute to a cheering crowd.