How do i cal second question in a window?

Hi All,

I have i window in that one question and 4 Toggle buttons. and one next button.

My task is if i click the next button i need to display the second question in the same window.

I wrote code like this:

 void DoMyWindow4(int windowID)
 { 
    GUI.Label(new Rect(10,10,500,100),"1) A pendulum length is 20m , find the Timeperiod of the pendulum ?",newfontStyle);
   toggleTxt1 = GUI.Toggle(new Rect(30, 50, 150, 40), toggleTxt1, " 8.975s");
   toggleTxt2 = GUI.Toggle(new Rect(130, 50, 150, 40), toggleTxt2, " 9.975s");
   toggleTxt3 = GUI.Toggle(new Rect(250, 50, 150, 40), toggleTxt3, " 7.975s");
   toggleTxt4 = GUI.Toggle(new Rect(350, 50, 150, 40), toggleTxt4, " 6.975s");
   
   if(GUI.Button(new Rect(500,50,50,30), "NEXT"))
     {
       GUI.Label(new Rect(10,10,500,100),"2) A pendulum time period is  15s , find the Length of the pendulum ?",newfontStyle);
   toggleTxt1 = GUI.Toggle(new Rect(30, 50, 150, 40), toggleTxt1, " 10.975cm");
   toggleTxt2 = GUI.Toggle(new Rect(130, 50, 150, 40), toggleTxt2, "15.975cm");
   toggleTxt3 = GUI.Toggle(new Rect(250, 50, 150, 40), toggleTxt3, " 13.975cm");
   toggleTxt4 = GUI.Toggle(new Rect(350, 50, 150, 40), toggleTxt4, " 9.975cm");
   
     }
 }

that is my window. But if i click the next button that question didn't change.

can i get any solution or any help.

Thankyou

Shankar