well formed XML DTD

Question

w3schools validator를 통해 XML/DTD를 실행했는데 오류가 발생했다는 것을 알려줍니다. 내가 뭘 잘못하고있는 걸까요? 내가 인정할 것이다 내가 XML

당신의 XML 문서을 잘 형성 하지만 유효하지

<?xml version="1.0" encoding="iso-8859-1" standalone="yes"?> 
<!DOCTYPE WEBDESIGNTOPICS [ 
<!ELEMENT WEBDESIGNTOPICS (topic+,topicname+,description+,provided)> 
<!ELEMENT topic (#PCDATA)> 
<!ELEMENT topicname (#PCDATA)> 
<!ELEMENT description (#PCDATA)> 
<!ELEMENT provided (#PCDATA)> 
]> 
<WEBDESIGNTOPICS> 
<topic> 
    <topicname>HTML5</topicname> 
    <description>HAMILTON</description> 
    <provided>SALESMAN</provided> 

</topic> 
<topic> 
    <topicname>CSS/CSS3</topicname> 
    <description>SMITH</description> 
    <provided>CLEANER</provided> 

</topic> 
<topic> 
    <topicname>PHP</topicname> 
    <description>JONES</description> 
    <provided>MANAGER</provided> 
</topic> 
<topic> 
    <topicname>JavaScript</topicname> 
    <description>JONES</description> 
    <provided>MANAGER</provided> 
</topic> 
<topic> 
    <topicname>jQuery</topicname> 
    <description>JONES</description> 
    <provided>MANAGER</provided> 
</topic> 
</WEBDESIGNTOPICS>