One key difference between the message form and the plain form is that RDF: about is used to identify the issue resource, however, it is not declared in-line using an id.

消息形式和一般形式的一个关键的区别是，rdf： about用来识别问题资源，但是，它没有内联地使用标识来声明。

youdao

He explained his position many times in speeches,debates and letters, including this one written in eighteen fifty-eight: I have made it equally plain that I think the negro is included in the word "men" used in the Declaration of Independence.

VOA: special.2009.02.09