public void GenerateQuestion()
    {
        if (!active)
        {
            return;
        }

        int index = GetNexQuestionIndex();

        if (index == -1) //if has no questions
        {
            return;
        }
        else if (index == -2) //if finish questions
        {
            GameManager.Instance.OnFinishQuestions();
            HideQuestionAndStop();
            return;
        }

        Question    question    = questions[index];
        AnswerGroup answerGroup = new AnswerGroup(question, answerPrefab);

        answerGroup.SetPosition(spawnPosition.position, answerDistance);
        answerGroup.StartMovement(answerSpeed);

        //set question text
        questionImage.sprite = question.question;
    }