$re = '/^(&|also|a|about|again|all|after|are(nt)?|arent|as|an(y)?|at|
bcuz|before|be(low)?|between|bring|but|by|and|can(not)?|close(d)?|could(nt)?|
cuz|do(nt)?|down|decide(d)?|decision|on(to)?|or|of|our|over|out|have(nt)?|he(re)?|
her|his|other(s)?|even|got(ten)?|for|from|get(s)?|got(ten)?|has(nt)?|havent|he(s)?|
him|his|if|in|to|in(to)?|is(nt)?||make|me|once|play(ed)?|role|say(s)?|seen|she(s)?|
should(nt)?|stop(ped)?|time|my|no(t)?|must(nt)?|now|you(re)?|your|want|want(ed)?|
watch(ed)?|way|we(re)?|will|with||i|a|is(nt)?|just|would(nt)?|before|that|the(re)?|
their|them|they|this|turn|when|at|how|it(s)?|which|who|after|then|if|how|because|know(s)?|
yet|[A-Za-z]{1,2}|http(s)?://.*|www\..*)$/x';
$str = 'why should havent also a yet their';
preg_match_all($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