You are looking at the HTML representation of the XML format.
HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query-continue>
    <allimages gaicontinue="05组.pdf" />
  </query-continue>
  <query>
    <pages>
      <page pageid="10838" ns="6" title="文件:--李杨战队ppt--.pdf" />
      <page pageid="11330" ns="6" title="文件:0.jpg" />
      <page pageid="9705" ns="6" title="文件:0.png" />
      <page pageid="9669" ns="6" title="文件:000.jpg">
        <duplicatefiles>
          <df name="学习.jpg" user="第三专业学习小组" timestamp="2017-07-23T02:24:23Z" />
        </duplicatefiles>
      </page>
      <page pageid="9255" ns="6" title="文件:001.jpg" />
      <page pageid="11991" ns="6" title="文件:006qTMOuly8fob9x0kvu1j30ro0roabk-1-.jpg" />
      <page pageid="11189" ns="6" title="文件:01.jpg" />
      <page pageid="11293" ns="6" title="文件:02.jpg" />
      <page pageid="9733" ns="6" title="文件:03.png" />
      <page pageid="11549" ns="6" title="文件:0510周五下午第四组组得分.jpg" />
    </pages>
  </query>
</api>