垂悬现在分词的概念与改正方法
一、基本规则
按照英语语法的相关规则，现在分词或现在分词短语在句子中用作状语时，其逻辑主语必须与句子主语保持一致。如：
Knowing all this, they made me pay for the damage. 他们尽管了解这一切，还是要我赔偿损失。
Climbing to the top of the tower, we saw a magnificent view. 我们爬到塔顶后，看到了一片壮丽的景象。
Not knowing their language, he found it hard to get work. 由于不懂他们的语言，他发现找工作很困难。
Having failed my French exams, I decided to concentrate on science subjects. 我因法语考试不及格而决心专攻理科。
二、垂悬现在分词的错误实例
假若一个现在分词或现在分词短语在句子中用作状语时，它的逻辑主语与句子主语不一致，那么这个现在分词就叫垂悬的现在分词（或叫无依着的现在分词）。垂悬的现在分词通常被认为是不合语法的，是错误的。如：
误：Tying one end of the rope to his bed, the other end was thrown out of the window.
正：Tying one end of the rope to his bed, he threw the other end out of the window. 他把绳子的一头系在床上，另一头扔出窗外。
三、纠正垂悬分词错误的两种常用方法
要解决垂悬分词的错误，即解决分词的逻辑主语与句子主语不一致的问题，通常有两种方法：一是改变句子结构，使句子主语与分词一致；二是在分词前面添加分词自己的主语，构成分词的独立主格结构。如：
误：Guiding her, they stumbled through the street.
正：He guiding her, they stumbled through the street. 他引着她，两个人蹒跚地穿过那条街。
误：Being equal, I would buy the black dress not the white one.
正：Other things being equal, I would buy the black dress not the white one. 其他方面若都相同，我将买那件黑的衣服，不买那件白的。
误：She sat behind the table, resting in her hands.
正：She sat behind the table, her chin resting in her hands. 她坐在桌子后面，双手托着下巴。
误：A complex engine has many separate components, each performing a different function.
正：A complex engine has many separate components, each performing a different function. 一个复杂发动机有很多独立零部件，每个零部件具有不同作用。