c#线程顺序执行

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Threading;
namespace 线程同步
{
    class Program
    {
        static int num = 1;
        static void Main(string[] args)
        {
            test2();        
        }

//线程顺序执行方法1

static void test1()
        {
            Action act = () =>
            {
                num++;
                Console.WriteLine(num);
            };

Task.Factory.StartNew(act).ContinueWith(o => act()).ContinueWith(o=>act());

Console.ReadLine();
        }

//线程顺序执行方法2
        static void test2()
        {
            Action act = () =>
            {
                Console.WriteLine("this is 1");
            
            };

Action act2 = () =>
            {
               
                Console.WriteLine("this is 2");
            };

Action act3 = () =>
            {
                
                Console.WriteLine("this is 3");
            };

Thread t1 = new Thread(new ThreadStart(act));
            Thread t2 = new Thread(new ThreadStart(act2));
            Thread t3 = new Thread(new ThreadStart(act3));

t1.Start();
            t2.Start();
            t2.Join(); //主线程停止,执行t2
            t3.Start();
            t3.Join(); //主线程停止,执行t3

Console.ReadLine();
        }

}

}