<!DOCTYPE html>
<html>
<head>
<style type="text/css">
td { border: 1px solid green; }
</style>
</head>
<table>
 <tr>
  <td width="50%">A</td>
 </tr>
 <tr>
  <td width="100%">B</td>
 </tr>
 <tr>
  <td>
   <table width="100%">
    <tr>
     <td width="100%">The quick brown fox jumps over the lazy wordwrap</td>
    </tr>
   </table>
  </td>
 </tr>
</table>
</body>
</html>