Split sentence into all possible combinations of sub-sentences

SplitIntoAll.cs

using System;
using System.Collections.Generic;
using System.Linq;

namespace WhaHappen
{
    public static class StringExtensions
    {
        public static IEnumerable<String> SplitIntoAll(this String s, Char delimiter = ' ')
        {
            return s.SplitIntoAll(delimiter.ToString());
        }

        public static IEnumerable<String> SplitIntoAll(this String s, String delimiter = " ")
        {
            var tokens = s.Split(delimiter, StringSplitOptions.RemoveEmptyEntries);
            for (var i = 0; i != tokens.Length; i++)
            for (var j = 1; j != tokens.Length - i; j++)
                yield return String.Join(delimiter, tokens.Skip(i).Take(j));
        }
    }
}