4选一​ 123456789101112131415161718192021222324252627282930//两种，一种使用assign赋值语句，用三目运算符嵌套，不便于阅读`timescale 1ns/1nsmodule mux4_1(input [1:0]d1,d2,d3,d0,input [1:0]sel,output [1:0]mux_out);assign mux_out =...