Linq in C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
 
namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            DataClasses1DataContext dc = new DataClasses1DataContext();
            var benutzerListe = from ds in dc.Benutzers where ds.PLY=="33" select ds;
            foreach (var item in benutzerListe)
            {
                Console.WriteLine(item.Vorname + " " + item.Nachname);
                item.Vorname = "Rolf";
 
            }
 
            Benutzer bn = new Benutzer() { ID = "3", Nachname = "sdfs", PLY = "saf", Strasse = "dsf", Vorname = "dsfs", Wohnort = "dsf" };
 
 
            dc.Benutzers.InsertOnSubmit(bn);
            dc.SubmitChanges();
            Console.ReadKey();
        }
    }
}