public static function wrap($text, $phrase, $wrapper = '<strong class="highlight">\\1</strong>') {
		if(empty($text)) {
			return '';
		}
		if(empty($phrase)) {
			return $text;
		}
		if(is_array($phrase)) {
			foreach ($phrase as $word) {
				$pattern[] = '/(' . preg_quote($word, '/') . ')/i';
				$replacement[] = $wrapper;
			}
		}
		else {
			$pattern = '/('.preg_quote($phrase, '/').')/i';
			$replacement = $wrapper;
		}
		return preg_replace($pattern, $replacement, $text);
	}