diff --git a/web_admin/serializers/article_serializer.py b/web_admin/serializers/article_serializer.py
index 675591f..4e98e55 100644
--- a/web_admin/serializers/article_serializer.py
+++ b/web_admin/serializers/article_serializer.py
@@ -271,14 +271,14 @@ class ArticleQuestionSerializer(serializers.ModelSerializer):
         ans_obj = SurveyOption.objects.filter(survey=obj, is_answer=True).last()
         if ans_obj:
             return ans_obj.id
-        return str("None")
+        return None
 
     def get_attempted_answer(self, obj):
         """attempt question or not"""
         context_data = self.context.get('user')
         junior_article_obj = JuniorArticlePoints.objects.filter(junior__auth=context_data,
                                                                 question=obj).last()
-        if junior_article_obj:
+        if junior_article_obj and junior_article_obj.submitted_answer:
             return junior_article_obj.submitted_answer.id
         return None