前正无生意，且记Task.ContinueWith之用法。

using System;using System.Collections.Generic;using System.Diagnostics;using System.Linq;using System.Linq.Expressions;using System.Text;using System.Threading;using System.Threading.Tasks;namespace ConsoleApp2{    class Program    {        static void Main(string[] args)        {            Console.WriteLine("主线程开始");            Task
     
       task = Task
      
       .Run(() => {                Thread.Sleep(2000);                return Thread.CurrentThread.ManagedThreadId.ToString();            });            task.GetAwaiter().OnCompleted(() =>            {                Console.WriteLine(task.Result);            });            //ContonieWith会在task上一个任务执行完毕之后，继续执行新的任务            task.ContinueWith(m => { Console.WriteLine("第一个任务结束啦！我是第二个任务"); });            Console.WriteLine("主线程结束");            Console.Read();        }    }}