不一定是同时发生，比如Seeing the accident,I dailed 120很显然，是看到了事故，然后才打120你看一下嘛分词作状语（关键找逻辑主语） a)放在句首的分词往往看作时间状语1以及原因状语2 1. Looking (when I looked) at the picture, I couldn't help missing my middle school days. 2.Seriously injured, Allen was rushed to the hospital. =As he was seriously injured, Allen was rushed to the hospital. b)放在句中或句末常常看作为伴随状态(并列句) The girl was left alone in the room，weeping（crying ）bitterly. (但注意特殊：Generally/frankly speaking... / taken as a whole(总的来讲）不考虑逻辑主语，看作为独立成分)
