title: why I cannot validate my code and why I get an error mesage
body: <p>Hello I just started to learn XML and DTDs and I cannot get my code to validate. I am using notepad++ to validate my code.</p>
  
  <pre><code>&lt;?xml version="1.0"?&gt;
  &lt;!DOCTYPE A [
  
  
  &lt;!ELEMENT A (B,D,F)&gt;
  &lt;!ELEMENT B (C*)&gt;
  &lt;!ELEMENT C (#PCDATA)&gt;
  &lt;!ELEMENT D (F*)&gt;
  &lt;!ELEMENT F (#PCDATA)&gt;
  
  ]&gt;
  </code></pre>
  
  <p>also when I made a check XML syntax I get an error mesage in line 11 (the last one)</p>
  
  <pre><code>&lt;?xml version="1.0"?&gt;
  &lt;!DOCTYPE A SYSTEM "d3.dtd"&gt;
  
  
  &lt;A&gt;
      &lt;B&gt;
          &lt;C&gt;&lt;/C&gt;
          &lt;C&gt;&lt;/C&gt;
      &lt;/B&gt;
      &lt;F&gt;&lt;/F&gt;
  &lt;/A&gt;
  </code></pre>