django TemplateSyntaxError Invalid block tag: 'trans' -

after running runserver command following error:

templatesyntaxerror @ /questions/ invalid block tag: 'trans'

does know what's reason?

this template syntax:

     {% extends "two_column_body.html" %} {#      template split several     blocks included here     blocks within directory templates/main_page     relative skin directory      there no html markup in file #} <!-- questions.html --> {% block forejs %}     {% include "main_page/custom_head_javascript.html" %} {% endblock %} {% block title %}{% spaceless %}{% trans %}questions{% endtrans %}{% endspaceless %}{% endblock %} {% block content %}     {% include "main_page/tab_bar.html" %}     {% include "main_page/headline.html" %}     {# ==== begin: main_page/content.html === #}     <div id="question-list">         {% include "main_page/questions_loop.html" %}     </div>     {# ==== end: main_page/content.html === #}     {% include "main_page/paginator.html" %} {% endblock %} {% block sidebar %}     {% include "main_page/sidebar.html" %} {% endblock %} {% block endjs %}     <script type="text/javascript">         {# cant cache #}         askbot['settings']['showsortbyrelevance'] = {{ show_sort_by_relevance|as_js_bool }};         askbot['messages']['questionsingular'] = '{{ settings.words_question_singular|escapejs }}';         askbot['messages']['answersingular'] = '{{ settings.words_answer_singular|escapejs }}';         askbot['messages']['acceptownanswer'] = '{{ settings.words_accept_or_unaccept_own_answer|escapejs }}';         askbot['messages']['followquestions'] = '{{ settings.words_follow_questions|escapejs }}';     </script>     {% include "main_page/javascript.html" %}     {% include "main_page/custom_javascript.html" %} {% endblock %} <!-- end questions.html --> 

{% trans %}questions{% endtrans %} not correct format.

{% load i18n %} should @ top of template, or extended template using translations.

you can use {% trans "questions." %}

if you're going use blocks, need in format below:

{% blocktrans %}{{ value2translate }}{% endblocktrans %} 

more info here.