Comment block output

Hi,
Comment block shows the following output:

<ul>
  <li>
     <a href="#">Comment1</a>
     1 day 15 hours ago
  </li>
  <li>
    <a href="#">Comment2</a>
    2 days 5 hours ago
  </li>
</ul>

Is there a way to put the "1 day 15 hours ago" message inside SPAN tags? I would appreciate any idea! Thanks!