They worked very hard carrying food to their home.这句中我觉得hard后面为什么可以直接加动词ing,

问题描述:

They worked very hard carrying food to their home.这句中我觉得hard后面为什么可以直接加动词ing,
请大家帮我分析下语法,

加动词ing表示“carrying food to their home”是“worked very hard”的目的