$re = '/^(?!tom tom[^A-Za-z\'$])([A-Za-z\'$]+ [A-Za-z\'$]+) went to college/m';
$str = 'tom tom went to college
\'tom tom went to college
to\'m tom went to college
tom to\'m went to college
tom tom\' went to college
tom tom\'s went to college
tom tom$ went to college
';
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