Listing 3 (test2.xml) is an example of an invalid document.

清单3 (test2 . xml)是一个无效文档的示例。

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The second sample document, as shown in Listing 3, contains well-formed XML, but is an invalid document according to the corresponding XML schema since the required element is missing.

第二个示例文档如 清单 3 所示，它包含格式良好的 XML，但是根据相应的 XML 模式，它是无效的文档，因为缺少必需的 元素。

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Otherwise, unpredictable results can occur when you attempt to parse an XML document and it contains invalid data types or an unexpected structure.

否则，当想要解析一个XML文档，而这个文档内包含无效数据或预想之外的结构时，就会出现不可预料的结果。

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In addition, if any item on a customs declaration is missing, then the whole document becomes invalid.

ECONOMIST: Old Russian customs

But on Monday, a court in Sochi said Mr Lebedev's registration was invalid because he had failed to submit a financial document.

BBC: Lebedev barred from Sochi contest