When I came into the room,I found him ____ in writing his doctoral dissertation.A.involved B.involving C.concentrated D.concentratingWhy

分类: 作业答案 • 2021-12-19 11:43:29

问题描述：

When I came into the room,I found him ____ in writing his doctoral dissertation.
A.involved B.involving C.concentrated D.concentrating
Why

答

这是一个固定表达式,Fund sb done 发现某人做某事.