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?
问题描述：
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