using System;

using System.Collections.Generic;

using System.Text;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        var Lines = new List<string> {"John", "and Mary", "and Andy Smith", "Loyal Order", "of Moose", "Cineplex Movie Theater", "Center", "for the Blind"};

        //{"Mr. John and", "Mrs. Mary Smith", "The Foundation for", "the Lord's Children", "Widgets Incorporated", "Loyal Order of", "Bullwinkle the Moose"};

        var Builder = new StringBuilder();

        for (var i = 0; i < Lines.Count; i++)

        {

            var keywords = new List<string>{" ", "and", "of", "for", "at", "the"};

            if (i > 0)

            {

                if (keywords.Any(x => Lines[i].StartsWith(x + " ") || Lines[i - 1].EndsWith(" " + x)))

                {

                    Builder.Append(" ");

                }

                else

                {

                    Builder.AppendLine();

                }

            }

            Builder.Append(Lines[i]);

        }

​

        Console.WriteLine(Builder.ToString());

    }

}