`timescale 1ns/1ns module lca_4( input [3:0] A_in , input [3:0] B_in , input C_1 , output wire CO , output wire [3:0] S ); wire c1,c2,c3; wire cout1, cout2, cout3; wire [3:0] g, p; // 算出 G 和 P and a1 (g[0], A_in[0], B_in[0]); xo...