private void Timer1_Tick_1(object sender, EventArgs e)
{
t--;
lbl2.Text = t + "";
if (t <= 0)
{
timer1.Stop();
Form2 frm2 = new Form2();
frm2.Show();
frm2.setDiem(diem, loi);
t = 15;
Visible = false; //đóng form 1 lại
}
}
