来自db的php数据 - 保持选中单选按钮

Question

Please advise if I could somehow keep radio-buttons selected after posting an html form. It's a survey questions and answers where the data is coming from db per page by a page field in db. I know I could insert the data into response table on every page post and then retrieve it with where the answer selected but probably there is another way doing it. A Form: " >

            <input  type="<?php 
                $submit = ""; 
                if($page_id == 1 ) {
                    $submit = "hidden";
                } else {
                    $submit = "submit";
                }
                echo $submit; 
            ?>" name="Prev" value="<< Previous" id = "b1"

            />
            <input  type="<?php 
                $submit = ""; 
                if($page_id == $max_page ) {
                    $submit = "hidden";
                } else {
                    $submit = "submit";
                }
                echo $submit; 
            ?>" name="Next" value="Next >>" id = "b2" />
            <input  type="<?php 
                $submit = ""; 
                if($page_id <> $max_page ) {
                    $submit = "hidden";

... Data from DB:

$question_set = find_all_question_by_survey_page($safe_survey_id, $safe_page_id ); 
while($question = mysqli_fetch_assoc($question_set)) {
    $output .= "<li>";
    $output .= urlencode($question["position"]);
    $output .=".&nbsp;";
    $output .= wordwrap(htmlentities($question["question_text"]),110,"<br>
&nbsp;&nbsp;&nbsp;&nbsp;");
    $output .="<br /><br />";
        $answer_set = find_answers_for_question ($question["id"]); 
        $i = 0;
        $output .= "<ul style=\"list-style: none;\">";
        while($answer = mysqli_fetch_assoc($answer_set) and $i <= ( (int) urlencode($answer["position"]) -1 ) ) {
            $output .= "<li>";
            $output .= "<input type = \"Radio\" Name = "; //&nbsp;&nbsp;
            $output .= urlencode($question['position']); 
            $output .= " value= ";
            $output .= urlencode($answer["position"]); 
            $output .= " />";
            $output .= "&nbsp;&nbsp;";
            $output .= $letters[$i]; 
            $output .=")&nbsp;";
            $output .= wordwrap(htmlentities(mb_convert_encoding($answer["answer_text"], 'UTF-8', 'ASCII'), ENT_SUBSTITUTE, "UTF-8"),110,"<br>
&nbsp;&nbsp;&nbsp;&nbsp;");
                $output .= "</li>"; 

            $i++;
        }
        $output .= "</ul>";

...