$re = '/(?:(?:\w+ DT )?(?:\w+ JJ )*)?\w+ (?:N[NP]|PRN)/m';
$str = 'he PRN and CC bill NP could MOD hear VB them PRN on IN the DT large JJ balcony NN near IN the DT house NN
the DT big JJ store NN he PRN bought VBD ripe JJ bananas NN.';
$subst = "";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
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