其实在教程的每页都给出了详细的讲解，我将做些强调和补充。

Simple wire

特性assign 语句always 块
赋值对象只能赋值给 wire只能赋值给 reg
触发方式连续触发（右侧信号变化时）事件触发（如时钟边沿、电平变化）
适用场景组合逻辑（如门电路）时序逻辑（如寄存器）或复杂组合逻辑
赋值符号使用 =时序逻辑用 <=，组合逻辑用 =

Solution

module top_module( input in, output out );
   assign out = in;
endmodule

结合规则：
In a Verilog "continuous assignment" (assign left_side = right_side;), the value of the signal on the right side is driven onto the wire on the left side.

Four wires

Solution

module top_module( 
    input a,b,c,
    output w,x,y,z );

    assign w = a;
    assign x = b;
    assign y = b; 
    assign z = c;
    
endmodule

Inverter

module top_module( input in, output out );

    assign out = ~in;
    // ~ means NOT
endmodule

AND gate

这部分内容循循善诱，讲解细致。

If it sounds different, it's because I've started describing signals as being driven （ has a known value determined by something attached to it ） or not driven by something.
module top_module( 
    input a, 
    input b, 
    output out );

    assign out = a & b;
    // AND is '&', not '+'.
    
endmodule

NOR gate

module top_module( 
    input a, 
    input b, 
    output out );

    assign out = ~(a | b);
    
endmodule

XNOR gate

异或非门，也称为同或门。

module top_module( 
    input a, 
    input b, 
    output out );

    assign out = (a & b) | (~a & ~b);
    
endmodule

Declaring wires

`default_nettype none
module top_module(
    input a,
    input b,
    input c,
    input d,
    output out,
    output out_n   ); 

    wire and1;
    assign and1 = a & b;
    wire and2;
    assign and2 = c & d; 
    assign out = and1 | and2;
    assign out_n = ~out;
    
endmodule

7485 chip

module top_module ( 
    input p1a, p1b, p1c, p1d, p1e, p1f,
    output p1y,
    input p2a, p2b, p2c, p2d,
    output p2y );

    wire p2cp2d;
    assign p2cp2d = p2c & p2d;
    wire p2ap2b;  
    assign p2ap2b = p2a & p2b; 
    assign p2y = p2cp2d | p2ap2b; 
    wire p1ap1cp1b;
    assign p1ap1cp1b = p1a & p1c & p1b;  
    wire p1fp1ep1d;  
    assign p1fp1ep1d = p1f & p1e & p1d;  
    assign p1y = p1ap1cp1b | p1fp1ep1d;

endmodule