$re = '/<inventor sequence="[^"]*" designation="[^"]*">(.*?)<\/inventor>/m';
$str = '<inventor sequence="001" designation="us-only"><addressbook><last-name>Li</last-name><first-name>Shuo</first-name><address><city>Beijing</city><country>CN</country></address></addressbook></inventor><inventor sequence="002" designation="us-only"><addressbook><last-name>Liu</last-name><first-name>Xin Peng</first-name><address><city>Beijing</city><country>CN</country></address></addressbook></inventor><inventor sequence="003" designation="us-only"><addressbook><last-name>Sun</last-name><first-name>Sheng Yan</first-name><address><city>Beijing</city><country>CN</country></address></addressbook></inventor><inventor sequence="004" designation="us-only"><addressbook><last-name>Wang</last-name><first-name>Hua</first-name><address><city>Littleton</city><state>MA</state><country>US</country></address></addressbook></inventor><inventor sequence="005" designation="us-only"><addressbook><last-name>Wang</last-name><first-name>Jun</first-name><address><city>Littleton</city><state>MA</state><country>US</country></address></addressbook></inventor>';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php