关于It引导的句型的问题～我会追分,我愿散尽家财.Hefeltithisdutytoworkfortheworldpeace.这句话对吗?为什么不是Hefeltitishisdutytoworkfortheworldpeace.为什么不要那个is不是it+be+adj.+todosth

Question

关于It引导的句型的问题～我会追分,我愿散尽家财.
He felt it his duty to work for the world peace.这句话对吗?
为什么不是He felt it is his duty to work for the world peace.为什么不要那个is 不是 it+be+adj.+to do sth吗 最好把It引导的句型详细讲一遍

Answer 1

He felt (that) it was his duty to work for the world peace,这个句子是对的,that后面的是felt的宾语从句,一个完整的句子
He felt it his duty to work for the world peace. 这个句子肯定对的,feel+it+形容词/名词to do sth.
和上面不同的是,这个地方不是宾语从句,而是it做形式主语,真正的主语是to work for the world peace. 这个句子也等于He felt to work for the world peace was his duty.
it做形式主语,真正的主语在后面,类似的还有：I feel it useless to argue with him（我觉得没用,什么是没用呢?和他争论没用）
it+be+adj./n.+to do sth 是对的,如 It is his duty to work for the world peace
It is useless to argue with him
It is necessary to have a cellphone