Can I show the answers to a previous round of questions in webform?
Your question is not completely clear, but as I understand you want to load a custom set of dropdown options as a webform element.

You can do that from a custom module with the following example code:

/**
 * Implements hook_webform_select_options_info().
 * 
 * Defines a custom dropdown form element to be used with the Webform module.
 */
function YOURMODULE_webform_select_options_info() {
  $items['last_time_answered'] = array(
    'title' =&gt; t('Last time you answered'),
    'options callback' =&gt; '_YOURMODULE_get_options',
  );
  return $items;
}

/**
 * Generate "Last time answered" options for the current user.
 * 
 * Used for sample webform element.
 */
function _YOURMODULE_get_options() {
  // Your query goes here
  // Return should be an array with $value =&gt; $label structure.
  return array(
    1 =&gt; 'Option 1',
    2 =&gt; 'Option 2',
    3 =&gt; 'Option 3',
  );
}


I also suggest to drop in a custom validator to the webform:

/**
 * Implements hook_form_alter().
 */
function MYMODULE_form_alter(&amp;$form, &amp;$form_state, $form_id) {

  switch ($form_id) {
    // Sample webform custom validation
    case 'webform_client_form_1':
      $form['#validate'][] = '_YOURMODULE_validate_custom_field';
      $first = array_shift($form['#submit']);
      array_unshift($form['#submit'], $first, '_YOURMODULE_validate_custom_field');
      break;
  }

}

/**
 * Custom validation function for webform component.
 */
function _YOURMODULE_validate_custom_field() {
  foreach ($form['#node']-&gt;webform['components'] as $element_id =&gt; $element) {

    if ($element['form_key'] == 'last_time_answered') {

      // Perform the check here
      if ($element['value'] != 'Sample value') {
        form_set_error('', t('Validation message.'));
      }

    }

  }
}


To use this custom field, create a new webform element (select options) and choose your new list from the "Load a pre-built option list" dropdown.