using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Linq.Expressions;
using System.Xml.Linq;
class Program
{
static void Main(string[] args)
{
String aString = "this is a test";
IEnumerable query = from ch in aString where Char.IsUpper(ch) select ch;
}
}