形容词短语作状语的具体理解

She came over, eager to help.

比较：She came over and was eager to help.

She came over, (being) eager to help.

We stayed up late, anxious to finish the work.

比较：We stayed up late and was anxiouus to finish the work.

We stayed up late, (being) anxious to finish the work.

He arrived home, hungry and tired.

比较：He arrived home and was hungy and tired.

He arrived home, (being) hungry and tired.

以上三句中的形容词作状语其实是现在分词作状语，但系词be的现在分词作状语时，通常省略being。以上三句中的现在分词短语（形容词短语）均为伴随状语，补充说明主语在做谓语动作时所处的状态。

She lay awake half the night.

此句中形容词的作用与以上三句不同，注意以上三句中的形容词前有逗号，逗号前的主谓结构在意义和结构上都是完整的，状语是补充性质的（即非限制性的）。但此句中的lay如果没有形容词awake则意义不完整。因此此句中的lay(lie)是个系词，形容词awake是表语，句子为主系表结构。