说明：  　介绍主机模式、c/ s 模式、多级模式特征,以及相关联的INTERNET上的三级结构问题,并从应用角度对计算模式进行了深入探讨,阐述了C/ S的发展方向和趋势。
(Introduced a host mode, and c/s mode, multi-level mode characteristics, and associated on the INTERNET three structural problems, the calculation mode from the application point of view in-depth discussions on the direction and trend of development of the C/S.)