public static function sentence(array $words, $twoWordsConnector = null, $lastWordConnector = null, $connector = ', ')
    {
        if ($twoWordsConnector === null) {
            $twoWordsConnector = Yii::t('yii', ' and ');
        }
        if ($lastWordConnector === null) {
            $lastWordConnector = $twoWordsConnector;
        }
        switch (count($words)) {
            case 0:
                return '';
            case 1:
                return reset($words);
            case 2:
                return implode($twoWordsConnector, $words);
            default:
                return implode($connector, array_slice($words, 0, -1)) . $lastWordConnector . end($words);
        }
    }