<?php
 
function highlight($text, $words) {
    preg_match_all('~\w+~', $words, $m);
    if(!$m)
        return $text;
    $re = '~' . implode('|', $m[0]) . '~i';
    return preg_replace($re, '<b style="color:white;background-color:red;border-radius:2px;">$0</b>', $text);
}
$text = "this is a very famouse poem written by liegh hunt the post want to impress upon the importance";
$words ="very written hu want impor";
echo highlight($text, $words);

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