Although you could create a new element equivalent for any tag in a general DTD, this work is useless to you as an author unless the content models that would include the tag are also specialized.

虽然可以为一般dtd中的任何标记创建新的等价元素，但是除非内容模型包含也进行专门化的标记，否则这对作者来说毫无用处。

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DITA instead leans toward a different SGML reuse technique and provides each element with a conref attribute that can point to any other equivalent element in the same or any other topic.

DITA 倾向于采用一种不同的 SGML 重用技术，为每个元素提供了一个 conref 属性，可以指向同一主题或不同主题中的其他任何等价元素。

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The W3C XML Schema allows for a class of element types that generally appear in the same locations to be treated as a group of equivalent elements in type definitions.

W3C XML Schema允许一类通常出现在相同位置的元素类型在类型定义中作为一组相等元素处理。

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