using System;

using System.Threading.Tasks;

​

public class Program

{

    public static void Main()

    {

        Task task1 = new Task(() => Console.WriteLine("Task1 is executed"));

        task1.Start();

        Task task2 = Task.Factory.StartNew(() => Console.WriteLine("Task2 is executed"));

        Task task3 = Task.Run(() => Console.WriteLine("Task3 is executed"));

        Console.WriteLine(task1.IsCompleted);

        task1.Wait(); // ожидаем завершения задачи task1

        task2.Wait(); // ожидаем завершения задачи task2

        task3.Wait(); // ожидаем завершения задачи task3

        Console.WriteLine(task1.IsCompleted);

    }

} //https://metanit.com/sharp/tutorial/12.1.php

​