diff --git a/BUGS.md b/BUGS.md
index fbf6761..dbcb1b5 100644
--- a/BUGS.md
+++ b/BUGS.md
@@ -1,6 +1,7 @@
 
 # BUGS
 
+- reload do teste recomeça a contagem no inicio do tempo.
 - em admin, quando scale_max não é 20, as cores das barras continuam a reflectir a escala 0,20. a tabela teste na DB não tem a escala desse teste.
 - em grade.html as barras estao normalizadas para os limites scale_min e max do teste actual e nao dos testes realizados no passado (tabela test devia guardar a escala).
 - codigo `hello   world` nao esta a preservar o whitespace. O renderer de markdown gera a tag <code> que não preserva whitespace. Necessario adicionar <pre>.
@@ -8,6 +9,7 @@
 - a revisao do teste não mostra as imagens.
 - Test.reset_answers() unused.
 - teste nao esta a mostrar imagens de vez em quando.???
+- testar as perguntas todas no início do teste como o aprendizations.
 
 # TODO
 
@@ -17,10 +19,8 @@
 ou usar push (websockets?)
 - mudar ref do test para test_id (ref já é usado nas perguntas)
 - servidor ntpd no x220 para configurar a data/hora dos portateis dell
-- autorização dada, mas teste não disponível até que seja dada ordem para começar.
+- sala de espera: autorização dada, mas teste não disponível até que seja dada ordem para começar.
 - alunos com necessidades especiais nao podem ter autosubmit. ter um autosubmit_exceptions: ['123', '456']
-- mostrar unfocus e window area em /admin
-- testar as perguntas todas no início do teste.
 - submissao fazer um post ajax?
 - adicionar opcao para eliminar um teste em curso.
 - enviar resposta de cada pergunta individualmente.
@@ -52,13 +52,14 @@ ou usar push (websockets?)
 - se ocorrer um erro na correcçao avisar aluno para contactar o professor.
 - abrir o teste numa janela maximizada e que nao permite que o aluno a redimensione/mova?
 - detectar scroll e enviar posição para servidor (analise de scroll para detectar copianço? ou simplesmente para analisar como os alunos percorrem o teste)
-- aviso na pagina principal para quem usa browser da treta
+- aviso na pagina principal para quem usa browser incompativel ou settings esquisitos... Apos login pode ser enviado e submetido um exemplo de teste para verificar se browser consegue submeter? ha alunos com javascript bloqueado?
 - criar perguntas de outros tipos, e.g. associação, ordenação, varios textinput
-- perguntas para professor corrigir mais tarde.
+- perguntas para professor corrigir mais tarde. permitir que review possa alterar as notas
 - fazer uma calculadora javascript e por no menu. surge como modal
 
 # FIXED
 
+- mostrar unfocus e window area em /admin
 - CRITICAL se answer for `i<n` a revisão de provas mostra apenas i (interpreta `<` como tag?)
 - botao de autorizar desliga-se, fazer debounce.
 - link na pagina com a nota para voltar ao principio.
diff --git a/perguntations/__init__.py b/perguntations/__init__.py
index ffda1c7..11f2850 100644
--- a/perguntations/__init__.py
+++ b/perguntations/__init__.py
@@ -32,7 +32,7 @@ proof of submission and for review.
 '''
 
 APP_NAME = 'perguntations'
-APP_VERSION = '2020.11.dev1'
+APP_VERSION = '2020.11.dev2'
 APP_DESCRIPTION = __doc__
 
 __author__ = 'Miguel Barão'
diff --git a/perguntations/app.py b/perguntations/app.py
index 8f46466..533046a 100644
--- a/perguntations/app.py
+++ b/perguntations/app.py
@@ -50,6 +50,7 @@ async def hash_password(password):
 
 
 # ============================================================================
+# main application
 # ============================================================================
 class App():
     '''
@@ -66,10 +67,10 @@ class App():
 
     # ------------------------------------------------------------------------
     @contextmanager
-    def db_session(self):
+    def _db_session(self):
         '''
         helper to manage db sessions using the `with` statement, for example:
-        with self.db_session() as s:  s.query(...)
+        with self._db_session() as s:  s.query(...)
         '''
         session = self.Session()
         try:
@@ -98,23 +99,29 @@ class App():
         engine = create_engine(database, echo=False)
         self.Session = sessionmaker(bind=engine)
         try:
-            with self.db_session() as sess:
+            with self._db_session() as sess:
                 num = sess.query(Student).filter(Student.id != '0').count()
         except Exception as exc:
             raise AppException(f'Database unusable {dbfile}.') from exc
         logger.info('Database "%s" has %s students.', dbfile, num)
 
-        # pre-generate tests
-        logger.info('Generating tests for %d students...', num)
-        self._pregenerate_tests(num)
-        logger.info('Tests done.')
-
         # command line option --allow-all
         if conf['allow_all']:
             self.allow_all_students()
+        elif conf['allow_list'] is not None:
+            self.allow_list(conf['allow_list'])
         else:
             logger.info('Students not yet allowed to login.')
 
+        # pre-generate tests
+
+        if self.allowed:
+            logger.info('Generating %d tests. May take awhile...',
+                        len(self.allowed))
+            self._pregenerate_tests(len(self.allowed))
+        else:
+            logger.info('No tests were generated.')
+
     # ------------------------------------------------------------------------
     async def login(self, uid, try_pw):
         '''login authentication'''
@@ -123,7 +130,7 @@ class App():
             return False
 
         # get name+password from db
-        with self.db_session() as sess:
+        with self._db_session() as sess:
             name, password = sess.query(Student.name, Student.password)\
                                  .filter_by(id=uid)\
                                  .one()
@@ -183,31 +190,34 @@ class App():
 
     # ------------------------------------------------------------------------
     def _pregenerate_tests(self, num):
-        for _ in range(num):
-            event_loop = asyncio.get_event_loop()
-            test = event_loop.run_until_complete(self.testfactory.generate())
-            self.pregenerated_tests.append(test)
+        event_loop = asyncio.get_event_loop()
+        # for _ in range(num):
+        #     test = event_loop.run_until_complete(self.testfactory.generate())
+        #     self.pregenerated_tests.append(test)
+
+        self.pregenerated_tests += [
+                event_loop.run_until_complete(self.testfactory.generate())
+                for _ in range(num)]
 
     # ------------------------------------------------------------------------
     async def generate_test(self, uid):
-        '''generate a test for a given student'''
-        if uid in self.online:
-            try:
-                test = self.pregenerated_tests.pop()
-            except IndexError:
-                logger.info('"%s" generating new test.', uid)
-                test = await self.testfactory.generate()  # student_id) FIXME
-            else:
-                logger.info('"%s" using pregenerated test.', uid)
+        '''generate a test for a given student. the student must be online'''
+
+        student_id = self.online[uid]['student']  # {'name': ?, 'number': ?}
 
-            student_id = self.online[uid]['student']  # {number, name}
-            test.start(student_id)
-            self.online[uid]['test'] = test
+        try:
+            test = self.pregenerated_tests.pop()
+        except IndexError:
+            logger.info('"%s" generating new test...', uid)
+            test = await self.testfactory.generate()
             logger.info('"%s" test is ready.', uid)
-            return self.online[uid]['test']
+        else:
+            logger.info('"%s" using a pregenerated test.', uid)
 
-        # this implies an error in the program, code should be unreachable!
-        logger.critical('"%s" is offline, can\'t generate test', uid)
+        test.start(student_id)           # student signs the test
+        self.online[uid]['test'] = test  # register test for this student
+
+        return self.online[uid]['test']
 
     # ------------------------------------------------------------------------
     async def correct_test(self, uid, ans):
@@ -236,7 +246,7 @@ class App():
         logger.info('"%s" saved JSON.', uid)
 
         # --- insert test and questions into database
-        with self.db_session() as sess:
+        with self._db_session() as sess:
             sess.add(Test(
                 ref=test['ref'],
                 title=test['title'],
@@ -273,7 +283,7 @@ class App():
         test.save_json(fpath)
 
         # insert test into database
-        with self.db_session() as sess:
+        with self._db_session() as sess:
             sess.add(Test(ref=test['ref'],
                           title=test['title'],
                           grade=test['grade'],
@@ -309,7 +319,7 @@ class App():
         '''generates a CSV with the grades of the test'''
         test_id = self.testfactory['ref']
 
-        with self.db_session() as sess:
+        with self._db_session() as sess:
             grades = sess.query(Question.student_id, Question.starttime,
                                 Question.ref, Question.grade)\
                          .filter(Question.test_id == test_id)\
@@ -338,7 +348,7 @@ class App():
 
     def get_test_csv(self):
         '''generates a CSV with the grades of the test'''
-        with self.db_session() as sess:
+        with self._db_session() as sess:
             grades = sess.query(Test.student_id, Test.grade,
                                 Test.starttime, Test.finishtime)\
                          .filter(Test.ref == self.testfactory['ref'])\
@@ -360,21 +370,21 @@ class App():
 
     def get_student_grades_from_all_tests(self, uid):
         '''get grades of student from all tests'''
-        with self.db_session() as sess:
+        with self._db_session() as sess:
             return sess.query(Test.title, Test.grade, Test.finishtime)\
                        .filter_by(student_id=uid)\
                        .order_by(Test.finishtime)
 
     def get_json_filename_of_test(self, test_id):
         '''get JSON filename from database given the test_id'''
-        with self.db_session() as sess:
+        with self._db_session() as sess:
             return sess.query(Test.filename)\
                        .filter_by(id=test_id)\
                        .scalar()
 
     def get_student_grades_from_test(self, uid, testid):
         '''get grades of student for a given testid'''
-        with self.db_session() as sess:
+        with self._db_session() as sess:
             return sess.query(Test.grade, Test.finishtime, Test.id)\
                        .filter_by(student_id=uid)\
                        .filter_by(ref=testid)\
@@ -399,7 +409,7 @@ class App():
     # --- private methods ----------------------------------------------------
     def _get_all_students(self):
         '''get all students from database'''
-        with self.db_session() as sess:
+        with self._db_session() as sess:
             return sess.query(Student.id, Student.name, Student.password)\
                        .filter(Student.id != '0')\
                        .order_by(Student.id)
@@ -433,13 +443,33 @@ class App():
         '''allow all students to login'''
         all_students = self._get_all_students()
         self.allowed.update(s[0] for s in all_students)
-        logger.info('Allowed all students.')
+        logger.info('Allowed all %d students.', len(self.allowed))
 
     def deny_all_students(self):
         '''deny all students to login'''
         logger.info('Denying all students...')
         self.allowed.clear()
 
+    def allow_list(self, filename):
+        '''allow students listed in file (one number per line)'''
+        try:
+            with open(filename, 'r') as file:
+                allowed_in_file = {s.strip() for s in file} - {''}
+        except Exception as exc:
+            error_msg = f'Cannot read file {filename}'
+            logger.critical(error_msg)
+            raise AppException(error_msg) from exc
+
+        enrolled = set(s[0] for s in self._get_all_students())  # in database
+        self.allowed.update(allowed_in_file & enrolled)
+        logger.info('Allowed %d students provided in "%s"', len(self.allowed),
+                    filename)
+
+        not_enrolled = allowed_in_file - enrolled
+        if not_enrolled:
+            logger.warning('  but found students not in the database:  %s',
+                           ', '.join(not_enrolled))
+
     def _focus_student(self, uid):
         '''set student in focus state'''
         self.unfocus.discard(uid)
@@ -462,7 +492,7 @@ class App():
         '''change password on the database'''
         if password:
             password = await hash_password(password)
-        with self.db_session() as sess:
+        with self._db_session() as sess:
             student = sess.query(Student).filter_by(id=uid).one()
             student.password = password
         logger.info('"%s" password updated.', uid)
@@ -470,7 +500,7 @@ class App():
     def insert_new_student(self, uid, name):
         '''insert new student into the database'''
         try:
-            with self.db_session() as sess:
+            with self._db_session() as sess:
                 sess.add(Student(id=uid, name=name, password=''))
         except exc.SQLAlchemyError:
             logger.error('Insert failed: student %s already exists?', uid)
diff --git a/perguntations/main.py b/perguntations/main.py
index a0ef770..bbf369c 100644
--- a/perguntations/main.py
+++ b/perguntations/main.py
@@ -32,10 +32,14 @@ def parse_cmdline_arguments():
         'included with this software before running the server.')
     parser.add_argument('testfile',
                         type=str,
+                        # nargs='+',  # TODO
                         help='tests in YAML format')
     parser.add_argument('--allow-all',
                         action='store_true',
                         help='Allow all students to login immediately')
+    parser.add_argument('--allow-list',
+                        type=str,
+                        help='File with list of students to allow immediately')
     parser.add_argument('--debug',
                         action='store_true',
                         help='Enable debug messages')
@@ -46,9 +50,12 @@ def parse_cmdline_arguments():
                         action='store_true',
                         help='Review mode: doesn\'t generate test')
     parser.add_argument('--port',
-                        type=int, default=8443,
+                        type=int,
+                        default=8443,
                         help='port for the HTTPS server (default: 8443)')
-    parser.add_argument('--version', action='version', version=APP_VERSION,
+    parser.add_argument('--version',
+                        action='version',
+                        version=APP_VERSION,
                         help='Show version information and exit')
     return parser.parse_args()
 
@@ -119,6 +126,7 @@ def main():
         'testfile': args.testfile,
         'debug':    args.debug,
         'allow_all': args.allow_all,
+        'allow_list': args.allow_list,
         'show_ref': args.show_ref,
         'review':   args.review,
         }
diff --git a/perguntations/serve.py b/perguntations/serve.py
index bafce34..d76dddd 100644
--- a/perguntations/serve.py
+++ b/perguntations/serve.py
@@ -518,6 +518,7 @@ def run_webserver(app, ssl_opt, port, debug):
     '''
 
     # --- create web application
+    logging.info('-----------------------------------------------------------')
     logging.info('Starting WebApplication (tornado)')
     try:
         webapp = WebApplication(app, debug=debug)
diff --git a/perguntations/static/css/test.css b/perguntations/static/css/test.css
index 2057143..d15d3d6 100644
--- a/perguntations/static/css/test.css
+++ b/perguntations/static/css/test.css
@@ -8,6 +8,11 @@ body {
     background: #bbb;
 }
 
+/*code {
+    white-space: pre;
+}
+*/
+
 /* Hack to avoid name clash between pygments and mathjax */
 .MathJax .mo,
 .MathJax .mi {
diff --git a/perguntations/static/popper.js b/perguntations/static/popper.js
deleted file mode 120000
index 8090f8d..0000000
--- a/perguntations/static/popper.js
+++ /dev/null
@@ -1 +0,0 @@
-../../node_modules/popper.js/dist/
\ No newline at end of file
diff --git a/perguntations/test.py b/perguntations/test.py
index 8c1c1da..1304231 100644
--- a/perguntations/test.py
+++ b/perguntations/test.py
@@ -48,7 +48,7 @@ class TestFactory(dict):
             'duration': 0,  # 0=infinite
             'autosubmit': False,
             'debug': False,
-            'show_ref': False
+            'show_ref': False,
             })
         self.update(conf)
 
@@ -122,7 +122,6 @@ class TestFactory(dict):
         if qmissing:
             raise TestFactoryException(f'Could not find questions {qmissing}.')
 
-
     # ------------------------------------------------------------------------
     def check_test_ref(self):
         '''Test must have a `ref`'''
@@ -223,7 +222,7 @@ class TestFactory(dict):
         self.check_grade_scaling()
 
     # ------------------------------------------------------------------------
-    async def generate(self):  #, student):
+    async def generate(self):
         '''
         Given a dictionary with a student dict {'name':'john', 'number': 123}
         returns instance of Test() for that particular student
@@ -235,27 +234,29 @@ class TestFactory(dict):
         nerr = 0  # count errors during questions generation
 
         for qlist in self['questions']:
-            # choose one question variant
-            qref = random.choice(qlist['ref'])
-
-            # generate instance of question
-            try:
-                question = await self.question_factory[qref].gen_async()
-            except QuestionException:
-                logger.error('Can\'t generate question "%s". Skipping.', qref)
-                nerr += 1
-                continue
-
-            # some defaults
-            if question['type'] in ('information', 'success', 'warning',
-                                    'alert'):
-                question['points'] = qlist.get('points', 0.0)
-            else:
-                question['points'] = qlist.get('points', 1.0)
-                question['number'] = qnum  # counter for non informative panels
-                qnum += 1
-
-            questions.append(question)
+            # choose list of question variants
+            choose = qlist.get('choose', 1)
+            qrefs = random.sample(qlist['ref'], k=choose)
+
+            for qref in qrefs:
+                # generate instance of question
+                try:
+                    question = await self.question_factory[qref].gen_async()
+                except QuestionException:
+                    logger.error('Can\'t generate question "%s". Skipping.', qref)
+                    nerr += 1
+                    continue
+
+                # some defaults
+                if question['type'] in ('information', 'success', 'warning',
+                                        'alert'):
+                    question['points'] = qlist.get('points', 0.0)
+                else:
+                    question['points'] = qlist.get('points', 1.0)
+                    question['number'] = qnum  # counter for non informative panels
+                    qnum += 1
+
+                questions.append(question)
 
         # setup scale
         total_points = sum(q['points'] for q in questions)
@@ -320,13 +321,20 @@ class Test(dict):
             question['answer'] = None
 
     # ------------------------------------------------------------------------
-    def update_answers(self, ans):
+    def update_answer(self, ref, ans):
+        '''updates one answer in the test'''
+        self['questions'][ref].set_answer(ans)
+
+    # ------------------------------------------------------------------------
+    def update_answers(self, answers_dict):
         '''
         Given a dictionary ans={'ref': 'some answer'} updates the answers of
-        the test. Only affects the questions referred in the dictionary.
+        multiple questions in the test.
+        Only affects the questions referred in the dictionary.
         '''
-        for ref, answer in ans.items():
-            self['questions'][ref]['answer'] = answer
+        for ref, ans in answers_dict.items():
+            self['questions'][ref].set_answer(ans)
+            # self['questions'][ref]['answer'] = ans
 
     # ------------------------------------------------------------------------
     async def correct(self):
@@ -351,7 +359,7 @@ class Test(dict):
         self['finish_time'] = datetime.now()
         self['state'] = 'QUIT'
         self['grade'] = 0.0
-        # logger.info('Student %s:  gave up.', self["student"]["number"])
+        logger.info('Student %s:  gave up.', self["student"]["number"])
         return self['grade']
 
     # ------------------------------------------------------------------------
--
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