解析错误：“语法错误，意外';'，期待T_FUNCTION”

Sample Code:

Config.php:
class Config {
    public $serverIP = "1.1.1.10";
}

DB.php:
require_once "/home/mysite/PHP/Config.php";
class DB extends Config {
    //DB related functions here..
}

research.php:
require_once "/home/mysite/PHP/DB.php";
class research extends DB {
    // Using DB functions to retrieve information from the research tables.
}
Config.php:
class Config {
    p