diff --git a/grader b/grader
--- a/grader
+++ b/grader
@@ -125,8 +125,12 @@
   exit(0)
 end
 
+grader_mode = 'queue'
 if ARGV.length >= 1
   GRADER_ENV = ARGV[0]
+  if ARGV.length >=2
+    grader_mode = ARGV[1]
+  end
 else
   GRADER_ENV = 'exam'
 end
@@ -140,21 +144,45 @@
 RAILS_ENV = 'development'
 require RAILS_APP_DIR + '/config/environment'
 
-talk 'Grader queue'
-while true
-  if check_stopfile    # created by calling grader stop
-    clear_stopfile
-    puts "stopped"
+case grader_mode
+when "queue"
+  talk 'Grader queue'
+  while true
+    if check_stopfile    # created by calling grader stop
+      clear_stopfile
+      puts "stopped"
+      exit(0)
+    end
+    
+    task = Task.find(:first, :order => 'created_at')
+    if task!=nil 
+      grade(task.submission_id)
+      task.destroy
+    else
+      sleep(1)
+    end
+  end
+  
+when "prob"
+  prob = Problem.find_by_name(ARGV[2])
+  if prob==nil
+    puts "cannot find problem: #{ARGV[2]}"
     exit(0)
   end
-
-  task = Task.find(:first, :order => 'created_at')
-  if task!=nil 
-    grade(task.submission_id)
-    task.destroy
-  else
-    sleep(1)
+  users = User.find(:all)
+  users.each do |u|
+    puts "user: #{u.login}"
+    last_sub = Submission.find(:first,
+                               :conditions => "user_id = #{u.id} and " +
+                               "problem_id = #{prob.id}",
+                               :order => 'submitted_at DESC')
+    if last_sub!=nil
+      grade(last_sub.id)
+    end
   end
 end
 
 
+                             
+  
+
diff --git a/std-script/check b/std-script/check
--- a/std-script/check
+++ b/std-script/check
@@ -44,6 +44,10 @@
 ##################
 # Your code here #
 ##################
+
+puts "YOU HAVE TO EDIT THE CHECKING CODE HERE: #{__FILE__}"
+exit(127)
+
 num_pattern = /^[0-9]*/
 if (output_file_content =~ num_pattern) == nil
   report_wrong.call