$re = '~[.?!]+\K\s+(?=[A-Z])~';
$str = 'Fry me a Beaver. Fry me a Beaver! Fry me a Beaver? Fry me Beaver no. 4?! Fry me many Beavers... End';
preg_match_all($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