>
<li id="comment-321804" class="pingback odd alt thread-odd thread-alt depth-1">
<div class="comment-body">
Pingback： <a href="http://www.sinkshark.com/archives/15.html" class="url" rel="ugc external nofollow">SinkShark » 题目：求 1+2+…+n</a> </div>
</li>
<li id="comment-389831" class="comment even thread-even depth-1">
<article id="div-comment-389831" class="comment-body">
<footer class="comment-meta">
<div class="comment-author vcard">
<img alt="" src="https://secure.gravatar.com/avatar/18b1f35a