private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {                                         over=System.currentTimeMillis();now1=((over-now) / (1000 * 60 * 60) % 60)+":"+((over-now)/ (1000 * 60)% 60)+":"+((over-now)/ 1000 % 60);String a=now1+"";jTextField7.setText(a);// TODO add your handling code here:
}

private void jMenuItem2ActionPerformed(java.awt.event.ActionEvent evt) {                                           jLabel1.setText("arithmetic"); jLabel2.setText("Please input number ：");jButton1.setText("Start");jLabel3.setText("The topic purpose ：");jButton2.setText("answer");jLabel5.setText("Your answer：");jLabel10.setText("correct answer：");jButton4.setText("Next question");jLabel9.setText("The time used for：");jLabel7.setText("Wrongc number ：   ");jLabel6.setText("All number ：      ");jLabel8.setText("correct ：         ");jButton3.setText("End of the answer");// TODO add your handling code here:

private void jMenu1ActionPerformed(java.awt.event.ActionEvent evt) {                                       // TODO add your handling code here:
}                                      private void jMenuItem3ActionPerformed(java.awt.event.ActionEvent evt) {                                           jLabel1.setText("四则运算"); jLabel2.setText("请输入题数：");jButton1.setText("开始做题");jLabel3.setText("题 目：");jButton2.setText("查看答案");jLabel5.setText("你的答案：     ");jLabel10.setText("正确答案：");jButton4.setText("下一题");jLabel9.setText("所用时间为：");jLabel7.setText("错  题  数：");jLabel6.setText("答  题  数：");jLabel8.setText("正  确  率：");jButton3.setText("结束答题");// TODO add your handling code here:
}

private void jMenuItem1ActionPerformed(java.awt.event.ActionEvent evt) {                                           jLabel1.setText("四則運算"); jLabel2.setText("請輸入題數：");jButton1.setText("開始做題");jLabel3.setText("題      目：");jButton2.setText("查看答案");jLabel5.setText(" 你的答案是：");jLabel10.setText("正確答案是：");jButton4.setText("下一題");jLabel9.setText("所用時間為 ：");jLabel7.setText("錯  題  數：");jLabel6.setText("答  題  數：");jLabel8.setText("正  確  率：");jButton3.setText("结束答題")；
// TODO add your handling code here:
}