one second delay

whats wrong with this c# code to create a one second delay?

using System;
using System.Diagnostics;
using System.Threading;
class Program
{
/* notes
Thread.Sleep(time);
*/
static void Main(string[] args)
{
Console.WriteLine("tTt");
Thread.Sleep(10000);
Console.WriteLine("fFf");
/string clear = "clear";
Console.WriteLine("clear");/
}
}