PHP QUIZ在用户运行测试时不显示问题及其选项

Question

这是负责显示问题及其选项的代码

if(isset($_SESSION['stdname']))
{
$result=executeQuery("select qnid, stdanswer,answered from studentquestion where stdid=".$_SESSION['stdid']." and testid=".$_SESSION['testid'].";");
$already_answered_qns = array();
while($r1=mysql_fetch_array($result))
{
    array_push($already_answered_qns, $r1['qnid']);
}


// select a question excluding the already answered questions
$result=executeQuery("select * from question where testid=".$_SESSION['testid']." and qnid not in (".implode(', ', $already_answered_qns).") Order by rand() ");
$r=mysql_fetch_array($result);
          ?>
          <div class="tc">

              <table border="0" width="100%" class="ntab">
                  <tr>
                      <th style="width:40%;"><h3><span id="timer" class="timerclass"></span></h3></th>
                      <th style="width:40%;"><h4 style="color: #af0a36;">Question No: <?php echo $_SESSION['qn']; ?> </h4></th>
                      <th style="width:20%;"><h4 style="color: #af0a36;"><input type="checkbox" name="markreview" value="mark"> Mark for Review</input></h4></th>
                  </tr>
              </table>
             <textarea cols="100" rows="8" name="question" readonly style="width:96.8%;text-align:left;margin-left:2%;margin-top:2px;font-size:120%;font-weight:bold;margin-bottom:0;color:#0000ff;padding:2px 2px 2px 2px;"><?php echo htmlspecialchars_decode($r['question'],ENT_QUOTES); ?></textarea>
              <table border="0" width="100%" class="ntab">
                  <tr><td>&nbsp;</td></tr>
                  <tr><td >1. <input type="radio" name="answer" value="optiona" <?php if((strcmp(htmlspecialchars_decode($r1['answered'],ENT_QUOTES),"review")==0 ||strcmp(htmlspecialchars_decode($r1['answered'],ENT_QUOTES),"answered")==0)&& strcmp(htmlspecialchars_decode($r1['stdanswer'],ENT_QUOTES),"optiona")==0 ){echo "checked";} ?>> <?php echo htmlspecialchars_decode($r['optiona'],ENT_QUOTES); ?></input></td></tr>
                  <tr><td >2. <input type="radio" name="answer" value="optionb" <?php if((strcmp(htmlspecialchars_decode($r1['answered'],ENT_QUOTES),"review")==0 ||strcmp(htmlspecialchars_decode($r1['answered'],ENT_QUOTES),"answered")==0)&& strcmp(htmlspecialchars_decode($r1['stdanswer'],ENT_QUOTES),"optionb")==0 ){echo "checked";} ?>> <?php echo htmlspecialchars_decode($r['optionb'],ENT_QUOTES); ?></input></td></tr>
                  <tr><td >3. <input type="radio" name="answer" value="optionc" <?php if((strcmp(htmlspecialchars_decode($r1['answered'],ENT_QUOTES),"review")==0 ||strcmp(htmlspecialchars_decode($r1['answered'],ENT_QUOTES),"answered")==0)&& strcmp(htmlspecialchars_decode($r1['stdanswer'],ENT_QUOTES),"optionc")==0 ){echo "checked";} ?>> <?php echo htmlspecialchars_decode($r['optionc'],ENT_QUOTES); ?></input></td></tr>
                  <tr><td >4. <input type="radio" name="answer" value="optiond" <?php if((strcmp(htmlspecialchars_decode($r1['answered'],ENT_QUOTES),"review")==0 ||strcmp(htmlspecialchars_decode($r1['answered'],ENT_QUOTES),"answered")==0)&& strcmp(htmlspecialchars_decode($r1['stdanswer'],ENT_QUOTES),"optiond")==0 ){echo "checked";} ?>> <?php echo htmlspecialchars_decode($r['optiond'],ENT_QUOTES); ?></input></td></tr>
                  <tr><td>&nbsp;</td></tr>
                  <tr>
                      <th style="width:80%;"><h4><input type="submit" name="<?php if($final==true){ echo "viewsummary" ;}else{ echo "next";} ?>" value="<?php if($final==true){ echo "View Summary" ;}else{ echo "Next";} ?>" class="subbtn"/></h4></th>
                      <th style="width:12%;text-align:right;"><h4><input type="submit" name="previous" value="Previous" class="subbtn"/></h4></th>
                      <th style="width:8%;text-align:right;"><h4><input type="submit" name="summary" value="Summary" class="subbtn" /></h4></th>
                  </tr>