多选题错判

app/helpers/exercise_helper.rb

@@ -43,8 +43,9 @@ module ExerciseHelper
     ecs.each do |ec|
       arr << ec.exercise_choice.choice_position
     end
-    arr.sort
-    arr = arr.join("")
+    #arr = arr.sort
+    str = arr.sort.join("")
+    return str
   end
 
   # 判断用户是否已经提交了问卷