Out of curiosity a port of love letter generator in c#

This is for my Harley-Queen(still waiting): this is a cook up code to tinker around:
 
using System;
using System.Text;
 
namespace LoveLetter
{
    internal class Program
    {
  static string NextRandomWord(string[] arr, Random rand) => arr[rand.Next(0, arr.Length)];
 
        private static void Main()
        {
            var salutation1 = new string[] { "Beloved", "Darling", "Dear",
          "Dearest", "Fanciful", "Honey" };
            var salutation2 = new string[] { "Chickpea", "Dear",
                      "Duck", "Jewel", "Love", "Moppet", "Sweetheart" };
            var adjs = new string[] { "affectionate", "amorous", "anxious",
            "avid", "beautiful", "breathless", "burning",
            "covetous", "craving", "curious", "eager", "fervent",
             "fondest", "loveable", "lovesick", "loving", "passionate",
           "precious", "seductive", "sweet", "sympathetic", "tender",
            "unsatisfied", "winning", "wistful" };
            var nouns = new string[] { "adoration", "affection", "ambition",
          "appetite", "ardour", "being", "burning", "charm", "craving",
           "desire", "devotion", "eagerness", "enchantment", "enthusiasm",
        "fancy", "fellow feeling", "fervour", "fondness", "heart", "hunger",
            "infatuation", "little liking", "longing", "love", "lust",
          "passion", "rapture", "sympathy", "thirst", "wish", "yearning" };
            var advs = new string[] { "affectionately", "ardently", "anxiously",
             "beautifully", "burningly", "covetously", "curiously",
        "eagerly", "fervently", "fondly", "impatiently", "keenly",
            "lovingly", "passionately", "seductively",
       "tenderly", "wistfully" };
            var verbs = new string[] { "adores", "attracts", "clings to",
             "holds dear", "hopes for", "hungers for", "likes",
       "longs for", "loves", "lusts after", "pants for", "pines for",
             "sighs for", "tempts", "thirsts for",
         "treasures", "yearns for", "woos" };
 
            int LONG = 1;
            int SHORT = 2;
            int? last = null;
            var rand = new Random();
            string ll;
            string concat = "";
            var builder = new StringBuilder();
            builder.Append($"{NextRandomWord(salutation1, rand)} 
                           { NextRandomWord(salutation2, rand)} \n");
            int numberOfLines = rand.Next(5, 7);
            for (var i = 0; i < numberOfLines; i++)
            {
                if (rand.Next(0, 9) < 5)
                {
                    //LONG
                    var optadj1 = (rand.Next(0, 9) < 5) ? "" : NextRandomWord(adjs, rand);
                    var noun1 = NextRandomWord(nouns, rand);
                    var optadv = (rand.Next(0, 9) < 5) ? "" : NextRandomWord(advs, rand);
                    var verb = NextRandomWord(verbs, rand);
                    var optadj2 = (rand.Next(0, 9) < 5) ? "" : NextRandomWord(adjs, rand);
                    var noun2 = NextRandomWord(nouns, rand);
                    if (last != null || last == LONG)
                    {
                        concat = ". ";
                    }
                    builder.Append($"{concat} My {optadj1} {noun1} {optadv} {verb} your 
                                     { optadj2}
                    { noun2}
                    ");
                    last = LONG;
                }
                else
                {
                    //SHORT
                    var adj = NextRandomWord(adjs, rand);
                    var noun = NextRandomWord(nouns, rand);
                    if (last == SHORT)
                    {
                        concat = ", ";
                    }
                    else if (last == LONG)
                    {
                        concat = ". You are";
                    }
                    else
                    {
                        concat = "You are ";
                    }
                    builder.Append($"{concat} my {adj} {noun}");
                    last = SHORT;
                }
            }
            ll = builder.ToString();
            var adv = NextRandomWord(advs, rand);
            ll += string.Format(".\n     Yours {0},\n     {1}.\n", adv, "Yourname");
            Console.WriteLine(ll);
            Console.ReadKey();
        }
    }
}