现在分词完成时的被动语态和过去分词均表示以下两层意思：一是动作先于主句动作完成，二是表示被动意义。其基本区别是，用现在分词完成时的被动语态比用过去分词更强调动作的完成；若不细区分，两者常可互换。如：

(Having been) asked to stay, I couldn’t very well leave. 人家请我留下，我就不好走了。

(Having been) warned of the danger, I took extra precautions. 被警告有危险后，我采敢了额外的防防措施。
(Having been) rejected by everybody, he became a monk. 众人都不和他来往，他就出家当了和尚。

(Having been) surrounded by the enemy，we must fight our way out. 我们已被敌人包围，必须杀出一条活路。