In this section, you see how to define two new content roots; each root contains the hierarchy of pages for its virtual portal.

在本节中，您将看到如何定义两个新的上下文根，每个根包含其虚拟门户的页面层次。

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The Order could be the root of another hierarchy in the data model.

订单可能是数据模型中的其他层次的根。

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Interface XMLEvent represents the root of this type hierarchy; all event types must extend this interface.

接口XMLEvent表示类型层次结构的根，所有类型的事件必须扩展该接口。

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