：（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) presupposes that the distribution of the physical block is free　(5) Find the replacement algorithm of the missing page number and the number of replacement