后一种形式建立了 2.0 中的隐含文档节点（Implicit Document Node，IDN），这是一种新增加的临时树 结构。

That latter form creates an Implicit Document Node (IDN) in 2.0, which is one form of the new temporary tree structure.

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另一方面的局限与从 xsl:variable 内容中调用命名模板时的结果树片段有关（参阅上一节 隐含文档节点）。

Another restriction is the limitation involved in result tree fragments when calling a named template from the content of xsl:variable. (See the earlier section, Implicit document nodes).

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