diff --git a/app/controllers/homework_commons_controller.rb b/app/controllers/homework_commons_controller.rb
index 98be8c699..e5df1f6ad 100644
--- a/app/controllers/homework_commons_controller.rb
+++ b/app/controllers/homework_commons_controller.rb
@@ -289,11 +289,11 @@ class HomeworkCommonsController < ApplicationController
 
   def get_next_work
     member = @course.course_member(current_user.id)
-    student_works = @homework.teacher_works(member).where.not(id: @homework.student_works_scores.where(reviewer_role: [1, 2]))
+    student_works = @homework.teacher_works(member).where.not(id: @homework.student_works_scores.where(reviewer_role: [1, 2]).pluck(:student_work_id))
     if params[:work_id]
       student_works = student_works.where.not(id: params[:work_id])
     end
-    @work = student_works.where("work_status > 0").take
+    @work = student_works.where("work_status > 0").sample(1).first
   end
 
   def update_score