<?php
$str = <<<EOT
<tr><th rowspan="3">价格</th>
<td class="f12">订货量(公斤)</td>
<td class="f12">价格(元/公斤)</td>
</tr><tr><td>1-999</td>
<td><span class="red">40.00</span></td>
</tr><tr><td>≥1000</td>
<td><span class="red">35.00</span></td>
</tr><tr><th>供货总量</th>
<td colspan="2">1000000000000公斤</td>
</tr><tr><th>产地</th>
<td colspan="2">陕西省/西安市</td>
</tr><tr><th>发货期</th>
<td colspan="2">自买家付款之日起2天内发货</td>
</tr>
EOT;
$pattern = '/<tr>[\w+]<\/tr>/i';
preg_match($pattern, $str, $match);
var_dump($match);
