你已经走上了正确的道路；只需为$parent_terms 围绕现有循环排列。此外，检查数组中的数字是否为有效的术语ID也是一个好主意，因此最终可能会执行以下操作：

$parent_terms = array( 1, 2, 3, 10 );
$taxonomy = \'products\';

echo \'<ul>\';
foreach ( $parent_terms as $parent_term_id ) {
  $parent_term = get_term_by( \'id\', $parent_term_id, $taxonomy );

  if ( $parent_term ) {
    echo \'<li><a href="\' . get_term_link( $parent_term_id, $taxonomy ) . \'">\' . $parent_term->name . \'</a>\';

    $child_terms = get_term_children( $parent_term_id, $taxonomy );
    if ( $child_terms ) {
      echo \'<ul>\';
      foreach ( $child_terms as $child_term_id ) {
        $child_term = get_term_by( \'id\', $child_term_id, $taxonomy );
        echo \'<li><a href="\' . get_term_link( $child_term_id, $taxonomy ) . \'">\' . $child_term->name . \'</a></li>\';
      } // end of child terms loop
      echo \'</ul>\';
    } // end of $child_terms

  echo \'</li>\';
  } // end of $parent_term

} // end of parent terms loop
echo \'</ul>\';

$parent_terms = array(); // define empty array
$term_options = ot_get_option(\'option-name\');
foreach ( $term_options as $term_option_id ) {
  // convert strings to numbers and save them in $parent_terms
  array_push( $parent_terms, intval($term_option_id) );
}