To define a subject, you create a DITA topic (typically a concept topic) to identify an aspect of the subject matter of your content (see Figure 2).

要定义主题，需要创建DITA题目(通常是内容题目)来标识内容的主题问题方面(请参阅图2)。

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SKOS lets you define the subjects for a particular subject matter area (organizing these subjects as a taxonomy if desired) and then classify each piece of content to indicate its subject.

SKOS允许定义具体主题问题范围的主题(如果希望，还可以把这些主题组织成分类系统)，然后对每部分内容进行分类，指出它的主题。

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Simple Knowledge Organization System (SKOS) provides a standard for indicating the subject matter of content.

简单知识组织系统(Simple Knowledge Organization System, SKOS)提供了指示内容的主题问题的标准。

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Open Educational Resources typically go beyond the textbook to incorporate interactive project-based learning methodologies that allow individualized, interactive engagement with subject matter content and personalized assessment of progress.

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