it作形式宾语——find/think/belive+形容词/名词/for sb.+to do sth.

题目

it作形式宾语——find/think/belive+形容词/名词/for sb.+to do sth.
例句：we all think it necessary to do exercise.
关于这个句式,为什么不是it+is+形容词/名词
即：we all think it's necessary to do exercise.
此时 it's necessary to do exercise不是作think的宾语从句吗?
两者有何区别?可以互相转换吗?

答案

很简单.我来告诉你.1 I think that it is necessary to do exercises.---------这是宾语从句,that是宾语从句的连接词,think是主句的谓语动词.that后面的是从句部分.2 we all think it necessary to do exercises.---...