Question

find sth to be adj.

Answer 1

这不是词组,是动词find 的用法之一：

find + 宾语 + 宾补（可以是adj., 也可以是 to be adj, 或者n等）.如：

I found the book interesting.

I found the book to be interesting.

I found it hard to learn a foreign language. (这里it 是形式宾语）

I found the book a great work.