Error: "The markup in the document preceding the root element must be well-formed"

Error: "The markup in the document preceding the root element must be well-formed"

创建时出现错误 RDF/XML:

The markup in the document preceding the root element must be well-formed

有人可以帮我解决这个错误吗?

<?xml version="1.0" encoding ="UTF-8"?>
<"rdf:RDF">
"xmlns:g=“http://schema.org/gen”
"xmlns:u=“http://schema.org/univ”>
<rdf:Description about="http://thisisjohnsmith.org">
    <dc:Title> Personal Webpage </dc:Title>
           <dc:Creator> John Smith </dc:Creator>
</rdf:Description>
<rdf:Person rdf:ID=“john”>
    <g:name>John Smith</g:name> 
    <g:age>40</g:age>
</rdf:Person> 
<rdf:Person rdf:ID=“peter”>
    <g:name>Peter</g:name>
</rdf:Person> 
 <rdf:Lecturer rdf:ID=“john”>
    <g:name>John Smith</g:name> 
</rdf:Lecturer> 
<rdf:Lecture rdf:ID=“john”>
    <g:name>John Smith</g:name> 
    <g:status>crowded</g:status> 
    <g:student>
    <g:name> Peter</g:name>
   </g:student>
</rdf:Lecture> 
</rdf:RDF>

有许多语法错误使您的 XML 格式不正确。

这是一份格式正确的文档副本:

<?xml version="1.0" encoding="UTF-8"?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
         xmlns:dc="http://purl.org/dc/elements/1.1/"
         xmlns:g="http://schema.org/gen">
  <rdf:Description rdf:about="http://thisisjohnsmith.org">
    <dc:Title> Personal Webpage </dc:Title>
    <dc:Creator> John Smith </dc:Creator>
  </rdf:Description>
  <rdf:Person rdf:ID="john">
    <g:name>John Smith</g:name> 
    <g:age>40</g:age>
  </rdf:Person> 
  <rdf:Person rdf:ID="peter">
    <g:name>Peter</g:name>
  </rdf:Person> 
  <rdf:Lecturer rdf:ID="john">
    <g:name>John Smith</g:name> 
  </rdf:Lecturer> 
  <rdf:Lecture rdf:ID="john">
    <g:name>John Smith</g:name> 
    <g:status>crowded</g:status> 
    <g:student>
      <g:name> Peter</g:name>
    </g:student>
  </rdf:Lecture>
</rdf:RDF>