You can validate an XML document on demand or automatically when you save the document.

可以在需要时验证XML文档，或在保存文档时自动验证。

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With a pull approach, on the other hand, the parser is effectively an iterator for going through the components of a document on demand.

相反，在使用拉方式的情况下，解析器实际上是一个高效的迭代器，可以根据需要对文档中的不同部分进行遍历。

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The On Demand mode exports a document immediately, while scheduled mode adds the document to a scheduled queue to be processed later.

On Demand模式立即导出文档，而Scheduled模式则将文档添加到计划队列中，留待以后处理。

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Diplomats at the United Nations are working on a document that would demand restrictions on oil and other commercial business with the Syrian regime if it refuses to implement the Annan peace plan for a cease-fire and a transitional government.

CNN: Clinton slams Russia, China over Syria

This usually means a refusal to supply a document or a piece of information on demand.

ECONOMIST: Jacob Soderman, wrist-tapper general