1L 第二题

<?xml version="1.0" encoding="gb2312"?>
<!DOCTYPE ARTICLE [
<!ELEMENT ARTICLE (TITLEPAGE,INTRODUCTION)>
<!ELEMENT TITLEPAGE (#PCDATA|SUBTITLE)*>
<!ELEMENT SUBTITLE (#PCDATA)>
<!ELEMENT INTRODUCTION ANY>
<!ELEMENT HEADING (#PCDATA)>
<!ENTITY title "The Story of XML <SUBTITLE>The Future Language of the Internet</SUBTITLE>">
<!ENTITY topics SYSTEM "Topics.xml">
]>
<ARTICLE>
<TITLEPAGE>
Title:
&title;
Author:Michael Young
</TITLEPAGE>
<INTRODUCTION>
Here *s what this article covers:
&topics;
</INTRODUCTION>
</ARTICLE>
第一题

谢谢楼主，楼主好人。