什么情况下用现在分词作伴随状语这种形式呢?

什么情况下用现在分词作伴随状语这种形式呢?例如 she turned a suitcase into a bed and put the children into it,covering them with all the clothes 这里为什么要用这种形式呢 如果我改成这样she turned a suitcase into a bed and put the children into it,she covered them with all the clothes 有什么变化了我想了解下现在分词作状语的用法 什么情况下用这种形式