Массовая замена тегов

  include('keywords.inc.php');
  function getKeywords($text){
 
        $params['content'] = $text; //page content
        $params['min_word_length'] = 5;  //minimum length of single words
        $params['min_word_occur'] = 1;  //minimum occur of single words
 
        $params['min_2words_length'] = 5;  //minimum length of words for 2 word phrases
        $params['min_2words_phrase_length'] = 10; //minimum length of 2 word phrases
        $params['min_2words_phrase_occur'] = 2; //minimum occur of 2 words phrase
 
        $params['min_3words_length'] = 5;  //minimum length of words for 3 word phrases
        $params['min_3words_phrase_length'] = 10; //minimum length of 3 word phrases
        $params['min_3words_phrase_occur'] = 2; //minimum occur of 3 words phrase
 
        $keyword = new autokeyword($params, "UTF-8");
 
        return $keyword->get_keywords();
 
    }
 
$text="10 сентября был вторник. В какой день недели выпадает 13 августа в этом году?";
 
echo getKeywords($text);