using System;

using System.Collections.Generic;

using System.Linq;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        string json = @"

            {

              ""sentences"": [

                {

                  ""0"": {

                    ""text"": ""huge success"",

                    ""begin"": 4,

                    ""end"": 6

                  },

                  ""1"": {

                    ""text"": ""new venture"",

                    ""begin"": 17,

                    ""end"": 19

                  },

                  ""2"": {

                    ""text"": ""comfort zone"",

                    ""begin"": 26,

                    ""end"": 28

                  },

                  ""length"": 3

                }

              ]

            }";

        JObject obj = JObject.Parse(json);

        List<Phrase> phrases = 

            obj["sentences"][0]

                .Children<JProperty>()

                .Where(jp => jp.Value.Type == JTokenType.Object)

                .Select(jp => jp.Value.ToObject<Phrase>())

                .ToList();

        foreach (Phrase p in phrases)

        {

            Console.WriteLine(string.Format("{0} ({1}, {2})", p.Text, p.Begin, p.End));

        }

    }

}

​

class Phrase

{

    public string Text { get; set; }

    public int Begin { get; set; }

    public int End { get; set; }

}

​