Three single arrays

My code result are 10, 10, 3, 7, 9, 9, 5, 5, 10, 10, 1 and i need other result 10, 3, 7, 9, 5, 1 how to do it ? Sorry for my bad english, but i hope youll understand that what i need to do.

I need help fast pls !

        int[] array1 = { 10, 3, 7, 9, 50, 5, 10, 21, 1};
        int[] array2 = { 1, 8, 7, 4, 10, 5, 9};
        int[] array3 = { 20, 3, 9, 5, 10, 1};


        Array.Sort(array2);
        Array.Reverse(array2);
        Array.Sort(array3);
        Array.Reverse(array3);



        int i = 0;
        int j = 0;

        Console.WriteLine("Second array descending");
        for (i = 0; i < array2.Length; i++)
        {
            Console.Write(array2[i].ToString() + ",");
        }
        Console.WriteLine();

        Console.WriteLine("Third array descending");

        for (j = 0; j < array3.Length; j++)
        {
            Console.Write(array3[j].ToString() + ",");
        }
        Console.WriteLine();

        Console.WriteLine("First array elements");

        foreach (int l in array1)
        {
            Console.Write(l + ",");
        }
        Console.WriteLine();
        Console.WriteLine();
        Console.WriteLine();
        Console.WriteLine();



        Console.WriteLine("Take elements from the first array");

        for (i = 0; i < array1.Length; i++)
        {

            for (j = 0; j < array2.Length; j++)

                {
                    for (j = 0; j < array3.Length; j++)

                    if (array1[i] == array2[j])
                    {

                        Console.Write(array1[i] + ",");

                    }

                    else if (array1[i] == array3[j])

                    {

                        Console.Write(array1[i] + ",");

                    }


                }

        }
        Console.WriteLine();




        Console.WriteLine();
        Console.WriteLine();
        Console.WriteLine();
    }

}

}