You have learned how to use a DTD to define the legal elements of an XML document, and how the DTD can be declared inside your XML document, or as an external reference.是什么意思_You have learned how to use a DTD to define the legal elements of an XML document, and how the DTD can be declared inside your XML document, or as an external reference.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句