题目内容：

I found unit 3 to be the most interesting.
感觉这个结构有点怪,为什么不说：I found unit 3 is the most interesting.

优质解答

find sth +宾补是正确的句型, to be the most interesting作宾补,可以看作强调其“interesting”的特点,而楼主提出的句子中is后面应为名词： the most interesting one才符合语法.