php 两层foreach循环如何给里层循环变量设置初始值=0

<?php foreach($questions as $k=>$question): ?>	        		<dl>		            	<dt class="knowledge_problem"><i><?php echo $k+1 ;?>.</i><span><?php echo $question['a']['question']; ?></span></dt>		                <dd>		            	<input type="hidden" id="<?php echo 'num'.($k+1) ;?>" name="<?php echo 'num'.($k+1) ;?>" value="<?php echo $question['a']['ID']; ?>"/>		                	<div class="answer clearfix">		                    	<ul>			                    	<?php foreach($answers as $i=>$answer): ?>			                     		<?php if($question['a']['ID'] == $answer['b']['idw_questions']): ?>				                        	<li class="<?php echo 'num0'.($i+1) ?>">				                            	<input type="radio" name="<?php echo $k+1 ?>" id="<?php echo $answers[$i]['b']['ID']; ?>"  value="<?php echo $answers[$i]['b']['ID']; ?>">				                				<label for="<?php echo $answer['b']['ID']; ?>"><?php echo $answer['b']['answer']; ?></label>				                            </li>										<?php endif ;?>			                        <?php endforeach; ?>		                        </ul>		                    </div>		                </dd>	        	    </dl>				<?php endforeach; ?>

<?phpecho '<meta http-equiv="content-type" content="text/html;charset=utf-8">';$questions = array(    '问题1',    '问题2',    '问题3');$answers = array(    array('选项a','选项b'),    array('选项c','选项d'),    array('选项e','选项f'));foreach($questions as $k=>$question){    echo 'Q'.($k+1).'<br>';    foreach($answers[$k] as $i=>$answer){        echo 'option'.($i+1).' '.$answer.'<br>';    }    echo '<br>';}?>