新概念英语第二册40课中的一句话

问题描述:

新概念英语第二册40课中的一句话
‘Her eyes were fixed on her plate and in a short time,she was very busy eating.’中谓语动词动词fix为什么用被动语态were fixed?

be fixed on是固定搭配,意为她盯着盘里的食物看了一小会