非谓语动词作状语时，它的逻辑主语应该是句子的主语。但有时非谓语动词带有自己的主语，从而在结构上与主语不发生关系，我们称之为独立主格结构（Absolute Construction）。其实，所谓“独立主格结构”也并非真正独立，它还是一种从属的结构。
一、 非谓语动词独立主格结构
在独立主格结构中，非谓语动词和它前面的名词或代词存在着逻辑上的主谓关系。
Such an able man to help you，you will surely succeed sooner or later.
有这么能干的人来帮你, 你迟早一定会成功的。（such an able man和 to help you 之间存在着主谓关系）
= Since such an able man will help you, you will surely succeed sooner or later.
He seating himself at the desk, his mother began to tell him a story.
他在书桌旁坐好后，他母亲开始给他讲故事。（seating himself at the desk拥有了自己的逻辑主语he，注意是“主格”）
= When he seated himself at the desk, his mother began to tell him a story.
The key to the bike lost, he had to walk to school.
由于丢了自行车钥匙，他只好步行去学校。（lost 的逻辑主语是the key，lost 也可以用完成式having been lost）
= Because the key to the bike had been lost, he had to walk to school.
A． 不定式“独立主格结构”
在“逻辑主语+动词不定式”结构中，动词不定式和它前面的名词或代词存在着逻辑上的主谓关系。这种结构也可用一个从句或并列分句来表达。
