Home work - merging in one collection

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Home_Work
{
    class Program
    {
        static void Main()
        {
            string[] source1 = { "Мама", "Папа", "Сын", "Дочь" };
            string[] source2 = { "Бабушка", "Дедушка", "Мама", "Папа" };
            List<string> words = new List<string>();

            FillListFromArray(words, source1);
            FillListFromArray(words, source2);

            ShowWords(words);
        }

        static void FillListFromArray(List<string> words, string[] source)
        {
            foreach (string word in source)
            {
                if (words.Contains(word) == false)
                {
                    words.Add(word);
                }
            }
        }

        static void ShowWords(List<string> words)
        {
            foreach(string word in words)
            {
                Console.Write(word + " ");
            }
        }
    }
}