它是指與主語之間無任何語法關系的名詞或代詞加上一個分詞的結構。它不修飾單個的詞，而修飾整個句子。獨立主格結構可位于句子的任何部位。它構成一個單獨實體，并具有如下兩種功能：(1) 解釋原因或情景 (2) 提供主句中重點部分的相關細節。

　　例 Freud distinguished three kinds of anxiety, each arising from a different source of perceived danger.

　　"each" 是獨立主格結構，"arising from"是動詞短語。注意這個獨立主格結構是一個"干巴巴"的句子。通過改變動詞形式，它的面貌可煥然一新：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.

　　有些短語在語法上可與它所在句中的其它成分分離。這種結構不修飾句子的任何一個詞，而修飾句子的整體意思。

　　分詞連同它所修飾的名詞或代詞可構成獨立主格結構。同位語和插入語有時也被認為是獨立主格結構

　　有用句型

　　During the early years of the Cultural Revolution, dried mushrooms on dinner tables were an unheard-of luxury, and pork chops unthinkable.

　　We see Van Gogh in the role of prophet in "Self Portrait," his emaciated, luminous head with its burning eyes set off against a whirlpool of darkness.

　　Professor Wang’s handwriting was precise, fussy, spidery, his notepad pale mauve.