什么是伴随状语从句??

伴随状语从句:用with引导的话,表示在进行一项动作的同时在进行另外一个动作,后面用名词+介词短语,或者直接用动词ing形式.如:The teacher came into the classroom,with books under her arm.She came here,with running.
复合结构就是用一些介词,副词来引导的句子,比较起简单句说有点复杂而已.如 she not only passes the exam but also get a high mark.用with的话,如 with his help,she get a high mark.其中with his help不过是一个状语成分,作条件讲.

过去分词作伴随状语

She stared at me, astonished.

她两眼望着我，十分惊异。

Einstein walked along the street, lost in thought.

爱因斯坦漫步街头，沉浸在思索之中。

所谓伴随，即一个主要动作做谓语，一个同时发生的动作或存在的状态做状语，即伴随状语，形式上常有介词with引导，动词则直接用动名词形势。如：
The teacher came in, holding a book in his hand.
The teacher came in with a book in his hand.

就是以上的回答，很具体