分词作状语，它的逻辑主语通常应是句子主语，否则会出错。请看下例。如：
(1) Finding her car stolen, ______.
A. a policeman was asked to help B. the area was searched thoroughly
C. it was looked for everywhere D. she hurried to a policeman for help
此题答案应选D，因为句首用作状语的现在分词短语finding her car stolen 的逻辑主语应是她，而不是 a policeman, the area, it 等。
在使用分词的逻辑主语时还要注意根据句意判断是主动还是被动，如：
(2) _____ many times, he still didnt understand it.
A. Having been told B. Though to be told
C. Having told D. He was told
根据句意，he 与 tell 应是被动关系。从时间上看，应该是被告诉在先，没有理解在后，故选A。比较下题由于句中用了并列连词but，情况有所不同。如：
(3) _____ many times, but he still didnt understand it.
A. Having been told B. Though he was told
C. To have been told D. He was told
此题答案选D，句中的并列连词 but 表明整个句子为并列句，同时表明 but 前应是一个独立的句子，而不能是一个非谓语动词短语(所以不能选A或C)。