带ING的形容词与动词ING形式做伴随状语如何区分

除作谓语动词的一部分和单独做名词用（动名词）外,动词 -ing 形式一般有三种句子功能：作形容词直接修饰名词：It's a coming car。（前置形容词）There is a car coming。（后置形容词）分词短语作后置定语：We have been trying to solve the problem troubling us for such a long time。这类后置定语短语是从后置定语从句简化而来：We have been trying to solve the problem (that has been) troubling us for such a long time,其 -ing 动词的逻辑主语是被修饰的名词,也称作“先行词”或者“前置词”。本句中 troubling 的先行词是 problem。分词短语作伴随状语：John is going to take up the job,knowing that he won't be able to come home in a year。与分词短语作后置定语的 -ing 形式不同,作伴随状语的分词短语的 -ing 动作的逻辑主语是句子的主语。本句中伴随状语的 -ing 动词 knowing 的逻辑主语是 John。实际上,-ing 形式的伴随状语是由两个同一主语的并列句简化而来。如上句：John is going to take up the job,and he knows that he won't be able to come home in a year。伴随状语通常用逗号与主句分开。