名词性从句，简言之就是作用相当于一个名词，那么想一想名词在英文中都能充当那些成分呢？
很容易就想到主语，宾语，表语，宾补，还有一个同位语
在英语中当这些成分是由一个句子来充当的时候，就产生了我们的名词性从句，不过请注意，英语中没有句子做宾补的情况。那么名词性从句就包含四类：主语从句，宾语从句，表语从句，同位语从句
例1. (That the most important duty of the gocernment is to improve the living stadand of its people) 主语从句has long been universally acknowledged.
2. I don't care (who you were before) 宾语从句；(What I really care) 主语从句
is (who will you become in the future)表语从句（即放在系动词后的从句）.
3. All of the people burst into tears when the news came (that a black had won the campaign),这是news 的同位语，解释说明news 的具体内容。.