public System.Data.Objects.ObjectQuery<T> CreateQuery<T> (string queryString, params System.Data.Objects.ObjectParameter[] parameters);

using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    string queryString =
        @"SELECT VALUE contact FROM AdventureWorksEntities.Contacts
            AS contact WHERE contact.FirstName = @fn";

    ObjectQuery<Contact> contactQuery =
        context.CreateQuery<Contact>(queryString,
            new ObjectParameter("fn", "Frances"));

    // Iterate through the collection of Contact items.
    foreach (Contact result in contactQuery)
        Console.WriteLine("First Name: {0}, Last Name: {1}",
        result.FirstName, result.LastName);
}