smarty的循环问题？

用两个section
<section name=index1 loop=arr1>
{if $index1%3 == 0}
<tr>
{/if}
<td>{$arr1[index1].className}<br/><table>
<section name=index2 loop=arr2>
<tr>
<td>{$arr2[index2][$arr1[index1].wzClassID].newsAuthor}</td>
<!-- ...... -->
</tr>
</section>
</table></td>
{if $index1%3 == 2}
</tr>
{/if}
</section>