【There was a large crowd in the square protesti】

问题补充：

There was a large crowd in the square protesting against the war.为什么protest要加ing?这是种什么用法?

答案：

protest是动词,这里做状语需要改为protesting

======以下答案可供参考======

供参考答案1:

现在分词短语做伴随状语的用法。