using System;

public class Program

{

    public static void Main()

    {

        bool? x = null;

        void show1() {

            Console.WriteLine(x ?? false || true);

        }

        void show2() {

            Console.WriteLine((x ?? false) || true);  //<<< if this is what you expect is equal to the above, you're mistaken

        }

        void show3() {

            Console.WriteLine(x ?? (false || true));

        }

        x = null;

        show1();

        show2();

        show3();

        Console.WriteLine();

        x = false;

        show1();

        show2();  //this is the odd one out, which shows you that ^^

        show3();

    }

}