Query
public void Linq21()
{
    List customers = GetCustomerList();
    
       var first3WAOrders = (
        from c in customers
        from o in c.Orders
        where c.Region == "WA"
        select new { c.CustomerID, o.OrderID, o.OrderDate })
        .Take(3);
    
       Console.WriteLine("First 3 orders in WA:");
    foreach (var order in first3WAOrders)
    {
        ObjectDumper.Write(order);
    }
}
Lambda Expression
public void Linq21()
{
    List customers = GetCustomerList();
 
    var first3WAOrders =
        (customers.SelectMany(cust => cust.Orders, (cust, order) => new {cust, order}).
                                    Where(@t => @t.cust.Region == "WA").Select(
                                        @t => new {@t.cust.CustomerID, @t.order.OrderID, @t.order.OrderDate}))
        .Take(3);
 
    Console.WriteLine("First 3 orders in WA:");
    foreach (var order in first3WAOrders)
    {
        ObjectDumper.Write(order);
    }
}
Output
First 3 orders in WA:
CustomerID=LAZYK OrderID=10482 OrderDate=3/21/1997
CustomerID=LAZYK OrderID=10545 OrderDate=5/22/1997
CustomerID=TRAIH OrderID=10574 OrderDate=6/19/1997