这个正则表达式怎么写,求教!!!!!
<tbody id="normalthread_728404">
<tr>
<td class="icn">
<a href="http://www.sqee.cn/thread-728404-1-1.html" title="有新回复 - 新窗口打开" target="_blank">
<img src="static/image/common/folder_new.gif" />
</a>
</td>
<th class="new">
<a href="javascript:;" id="content_728404" class="showcontent y" title="更多操作" onclick="CONTENT_TID='728404';CONTENT_ID='normalthread_728404';showMenu({'ctrlid':this.id,'menuid':'content_menu'})"></a>
<a class="tdpre y" href="javascript:void(0);" onclick="previewThread('728404', 'normalthread_728404');">预览</a>
<em>[<a href="http://www.sqee.cn/forum.php?mod=forumdisplay&fid=8&filter=typeid&typeid=21">宿迁资讯</a>]</em> <a href="http://www.sqee.cn/thread-728404-1-1.html" onclick="atarget(this)" class="s xst">仇和事件属实</a>
<span class="tps"> ...<a href="http://www.sqee.cn/thread-728404-2-1.html">2</a></span>
<a href="http://www.sqee.cn/forum.php?mod=redirect&tid=728404&goto=lastpost#lastpost" class="xi1">New</a>
</th>
<td class="by">
<cite>
<a href="http://www.sqee.cn/space-uid-202060.html" c="1">davalzhu</a></cite>
<em><span class="xi1"><span title="2015-7-31">7 小时前</span></span></em>
</td>
<td class="num"><a href="http://www.sqee.cn/thread-728404-1-1.html" class="xi2">35</a><em>5506</em></td>
<td class="by">
<cite><a href="http://www.sqee.cn/space-username-%CB%DE%C7%A8%C9%D8%C9%D8.html" c="1">宿迁韶韶</a></cite>
<em><a href="http://www.sqee.cn/forum.php?mod=redirect&tid=728404&goto=lastpost#lastpost"><span title="2015-7-31 18:02">2 小时前</span></a></em>
</td>
</tr>
</tbody>
想从上面中取出红色字部分,怎么取,正则表达式要怎么写