如何让线程一个接一个(而不是同时)运行,急!急!急!急!

Question

我的CODE是这样的(应该怎么改呢): 
    void   timerStart_Tick(object   serder,   EventArgs   e) 
                { 
                        try 
                        { 
                                        string strAppRunStartTime="202501";
                                        string   strNowTime   =   DateTime.Now.ToString("HHmmss"); 
                                        if   (strAppRunStartTime   ==   strNowTime) 
                                        { 
                                                Thread   t1=   new   Thread(new   ThreadStart(s1)); 
                                                t1.Priority   =   ThreadPriority.Highest; 
                                                t1.Start();                                                 Thread   t2=   new   Thread(new   ThreadStart(s2)); 
                                                t2.Priority   =   ThreadPriority.BelowNormal; 
                                                t2.Start();                                                 Thread   t3=   new   Thread(new   ThreadStart(s3)); 
                                                t3.Priority   =   ThreadPriority.BelowNormal; 
                                                t3.Start();                                                 Thread   t4=   new   Thread(new   ThreadStart(s4)); 
                                                t4.Priority   =   ThreadPriority.BelowNormal; 
                                                t4.Start(); 
                                        } 
                                } 
                        } 
                        catch   (Exception   err) 
                        { 
                                errMessage(err.Message,"timerStart_Tick"); 
                        } 
                }

Answer 1

private void S()
{
  s1();
  s2();
  s3();
  s4();
}Thread       t=       new       Thread(new       ThreadStart(S));   
t.Priority       =       ThreadPriority.BelowNormal;   
t.Start();

Answer 2

先初始化4个线程 然后
t1.start();
t1.join();
t2.start();
t2.join();
t3.start();
t3.join();
t4.start();