标准化考试小软件 要求每做完一个题目都把该题目的正确答案显示给用户

import  java.util.*; 
import  java.io.*; 
import  java.awt.*; 
import  java.awt.event.*; 
import  javax.swing.*;  
public  class  Example10_8 
{      public  static  void  main(String  args[]) 
        {    EWindow  w=new  EWindow(); 
              w.validate(); 
        } 
} 
class  EWindow  extends  Frame  implements  ActionListener,ItemListener 
{    String  str[]=new  String[7],s; 
      FileReader  file; 
      BufferedReader  in;    
      Button  start,next; 
      Checkbox  checkbox[]; 
      TextField  题目,分数; 
      int  score=0;  
      CheckboxGroup  age=new  CheckboxGroup(); 
      EWindow() 
      {    super( "英语单词学习 "); 
            分数=new  TextField(10);题目=new  TextField(70); 
            start=new  Button( "重新练习 "); 
            start.addActionListener(this); 
            next=new  Button( "下一题目 "); 
            next.addActionListener(this); 
            checkbox=new  Checkbox[4]; 
            for(int  i=0;i <=3;i++) 
              {    checkbox[i]=new  Checkbox( " ",false,age);