由于时间较长，而且当时的负责人已经不在了，所以要找出当时相关的证明文件比较困难，但是这个收费标准却是是经过当时的负责人确认了以后才收取的并且一直延续下来的。
參考答案:due to the long time,and the principal has been out of the company, so to find the relative documents is very difficult, but the standard charge is comformed by the principal above referred,and this standard continues all the time.