We did nothing but sit in the chair,looking at the mountains请举例说明用looking的原因

题目

We did nothing but sit in the chair,looking at the mountains请举例说明用looking的原因

答案

现在分词的用法,表是一个动作伴随着主句动作发生.
但是,根据一个句子一个谓语部分的原则,所以要用分词形式.
另外,分词的动作必须是句子主语发出的,否则就不能这么用.