：（1）从置换算法中任选2种；（2）建立页表；（3）设计的输入数据要能体现算法的思想（4）事先假定分配的物理块是空闲的；（5）求出各置换算法中的缺页次数和置换次数 -: (1) Choose from two kinds of replacement algorithm (2) building the page tables (3) design of the input data to reflect the thinking of the algorithm (4) presupp