PHP语法错误，意外“？”

Question

这是我的代码，我明白重要的是不要在同一行上混合使用html和php，但我无法理解这一点！有人可以帮忙吗？我尝试了一些替代方案，但我一直得到意外的语法错误'}'。

    <?php //Creating random number s
     $rid = rand(1,3); 
     echo $rid; if ($rid == 1){ ?>


     <form action="<?php echo base_url(); ?>index.php/welcome/result" method='post' id='quizForm' id='1'>

    <input type="hidden" name="id" value="1"/>
    <ol>


    <li>
    <h3>What does PHP stand for?</h3>

    <div>
    <input type='radio' name='answerOne' id='answerOne' value='A' />
    <label for='answerOneA'>A) Hyper text markup language</label>
    </div>

    <div>
    <input type='radio' name='answerOne' id='answerOne' value='B' />
    <label for='answerOneB'>B) PHP: Preprocessed hypertext</label>
    </div>

    <div>
    <input type='radio' name='answerOne' id='answerOne' value='C' />
    <label for='answerOneC'>C) PHP: Hypertext Preprocessor</label>
    </div>
    </li>


    <li>
    <h3>Who invented PHP?</h3>

    <div>
    <input type='radio' name='answerTwo' id='answerTwo' value='A' />
    <label for='answerTwoA'>A) Dick Dastardly </label>
    </div>

    <div>
    <input type='radio' name='answerTwo' id='answerTwo' value='B' />
    <label for='answerTwoB'>B) Rasmus Lerdof</label>
    </div>

    <div>
    <input type='radio' name='answerTwo' id='answerTwo' value='C' />
    <label for='answerTwoC'>C) God</label>
    </div>
    </li>



     <li>
    <h3>What is PHP used for?</h3>

    <div>
    <input type='radio' name='answerThree' id='answerThree' value='A' />
    <label for='answerThreeA'>A) Creating dynamic webpages</label>
    </div>

    <div>
    <input type='radio' name='answerThree' id='answerThree' value='B' />
    <label for='answerThreeB'>B) Server-side scripting</label>
    </div>

    <div>
    <input type='radio' name='answerThree' id='answerThree' value='C' />
    <label for='answerThreeC'>C) All of the above</label>
    </div>
    </li>
    </ol>
    <input type='submit' value='Submit Answers' />

    </form>
    <?php
     }
     ?>