1. 充当句子的状语。
2. 有自己的主语,同句子的主语不一致。
3. 名词(代词,形容词,副词,介词)+ 分词
4. With + 名词 (代词) + 分词 (形容词)
例:a) It being raining, I decided to stay at home.
b) Speech having been delivered, discussion started.
c) he entered the room, with his hands open(holding a rifle).