哪里做错了？解决办法

哪里做错了？
using System;
namespace tt
{
class cs
{
static void main()
{
zuobiao .mzuobiao mzb=new zuobiao.mzuobiao ();
mzb.xy();
Console .ReadKey ();
}
}
}
namespace zuobiao
{
public class mzuobiao
{
public void xy()
{
Console .WriteLine ("this is mzb...");
}
}
}

[解决办法]
static void Main