using System;

    public class Program

    {

        public static void Main()

        {

            var originalText = "{0} should be [this], and {2} should be [that], and there should be no [thus]";

            Console.WriteLine(originalText);

            var replacedText = string.Format(originalText, "this", "thus", "that");

            Console.WriteLine(replacedText);

        }

    }