private void btnSubmit_Click(object sender, EventArgs e)
        {
            if (tbPlayer.Text.Length < 2)
            {
                return;
            }
            //Check xem đã nối đúng chưa
            this.btnSubmit.Enabled = false;
            string NPC    = rtbNPC1.Text;
            string Player = tbPlayer.Text;

            if (game.CheckAnswer(NPC, Player) == true)
            {
                Correct();
                UsedWord.Add(Player);
            }
            else
            {
                Lose();
            }
        }