codice:
public class InsertTest {
    public static void Main() {

        string animal1 = "fox";
        string animal2 = "dog";

        string strTarget = String.Format("The {0} jumped over the {1}.", animal1, animal2);

        Console.WriteLine("The original string is:{0}{1}{0}", Environment.NewLine, strTarget);

        Console.Write("Please enter an adjective (or a group of adjectives) to describe the {0}: ==> ", animal1);
        string adj1 = Console.ReadLine();

        Console.Write("Please enter an adjective (or a group of adjectives) to describe the {0}: ==> ", animal2);    
        string adj2 = Console.ReadLine();

        adj1 = adj1.Trim() + " ";
        adj2 = adj2.Trim() + " ";

        strTarget = strTarget.Insert(strTarget.IndexOf(animal1), adj1);
        strTarget = strTarget.Insert(strTarget.IndexOf(animal2), adj2);

        Console.WriteLine("{0}The final string is:{0}{1}", Environment.NewLine, strTarget);
    }
}