大家帮忙看看这个ArrayList问题。（三个foreach中的输出语句为什么不输出）

Question

//测试ArrayList的用法
using System;
using System.Collections.Generic;
using System.Text;
using System.Collections;
namespace Struct
{
    class Student
    {
        
         ArrayList maths;
         ArrayList physics;
         ArrayList enghish;
         ArrayList chinese;        public void Maths()   //向maths中添加正数
        {
            maths = new ArrayList();
            int score= Convert.ToInt32(Console.ReadLine().ToString().Trim());
            if (score != 101)
            {
                maths.Add(score);
                
                Maths();
            }
            else
            {
                return;
            }
        }        public void Physics()   //向physics中添加正数
        {
            physics = new ArrayList();
            
            
            int score = Convert.ToInt32(Console.ReadLine().ToString().Trim());
            if(score!=101)
            {
                physics.Add(score);
               
                Physics();
            }                                                                        
            else
            {
                return;
            }
        }        public void Enghish()   //向enghish中添加正数
        {
            enghish = new ArrayList();
            int score = Convert.ToInt32(Console.ReadLine().ToString().Trim());
            if (score != 101)
            {
                enghish.Add(score);
               
                Enghish();
            }
            else
            {
                return;
            }
        }
        public void Chinese()  //向chinese中添加正数
        {
            chinese = new ArrayList();
            int score = Convert.ToInt32(Console.ReadLine().ToString().Trim());
            if (score != 101)
            {
                chinese.Add(score);
              
                Chinese();
            }
            else
            {
                return;
            }
        }
        public static  void Main()
        {            Student s = new Student();
            s.Maths();
            s.Physics();
            s.Enghish();
            s.Chinese();            foreach( object item in s.maths)  //输出maths中的值
            {
                Console.Write(item.ToString());
                
            }
            foreach (object item in s.physics)  //输出physics中的值
            {
                Console.Write(item.ToString());
                
            }
            Console.WriteLine();            foreach (object item in s.enghish) //输出enghist中的值
            {
                Console.Write(item.ToString());
                
            }
            foreach (object item in s.chinese) //输出chinese中的值
            {
                Console.Write(item.ToString());
                
            }
                      Console.Read();
        }
     }
    
}
/***
 foreach( object item in s.maths)  //输出maths中的值
            {
                Console.Write(item.ToString());
                
            }
            foreach (object item in s.physics)  //输出physics中的值
            {
                Console.Write(item.ToString());
                
            }
            Console.WriteLine();            foreach (object item in s.enghish) //输出enghist中的值
            {
                Console.Write(item.ToString());
                
            }
            foreach (object item in s.chinese) //输出chinese中的值
            {
                Console.Write(item.ToString());
                
            }****/这四个foreach中的Console.Write(item.ToString());为什么在命令行中不输出。四个ArrayList对象我已在命令行中输入了整数。

Answer 1

ArrayList maths= new ArrayList(); 如果在里初始化
public void Maths()  //向maths中添加正数 
每次都亲空了  
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Answer 2

 public Student()
 {
    maths = new ArrayList();
    Maths();
 }