网站不同于以物质媒体形式存在的图书,光盘或只播放一次的广播,其可持续的时间是不确定的,因此网站一旦投入运行后,还必须制定更新和维护的工作计划,以便及早发现问题并使今后的更新工作变得更加容易。-Compared with other second-handed book shop, the second-handed book trading market in the network is faster and more convenience. Yon can see in the netwo