public selection Add3(int id, selection question)
        {
            // 向试题表里增加试题
            question = db.selection.Add(question);
            include_question_between_bank_and_selection tmp = new include_question_between_bank_and_selection
            {
                BankID     = id,
                QuestionID = question.ID
            };

            // 向题库里增加试题
            db.include_question_between_bank_and_selection.Add(tmp);
            db.SaveChanges();
            return(question);
        }
        public bool Update3(int id, selection question)
        {
            selection tmp = db.selection.Where(p => p.ID == id).FirstOrDefault();

            if (tmp != null)
            {
                // 修改
                tmp.Content = question.Content;
                tmp.OptionA = question.OptionA;
                tmp.OptionB = question.OptionB;
                tmp.OptionC = question.OptionC;
                tmp.OptionD = question.OptionD;
                tmp.Answer  = question.Answer;
                tmp.Score   = question.Score;
                tmp.Type    = question.Type;
                db.SaveChanges();
                return(true);
            }
            else
            {
                return(false);
            }
        }