4. Extract Sentences by Keyword

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

class ExtractSentencesByKeyword
{

    static void Main()
    {
        char[] seperators = ".!?".ToCharArray();
        //char letter = 'A';
        //char[] seperatorsForSent = new char[177];
        //for (char i = (char)0; i <= 176; i++)
        //{
        //    if (!(i >= 65 && i <= 90 || i >= 97 && i<= 122 || i >= 48 && i <= 57 || i == 45))
        //    {
        //        seperatorsForSent[i] = i;
        //    }
        //}
        string word = Console.ReadLine();
        List<string> text = Console.ReadLine().Split(seperators).ToList();


        List<string[]> sentanses = new List<string[]>();

        for (int i = 0; i < text.Count; i++)
        {
            text[i] = text[i].Trim();
            string[] sentans = text[i].Split();

            if (sentans.Contains(word))
            {
                sentanses.Add(sentans);
            }
        }

        foreach (var sentans in sentanses)
        {
            Console.WriteLine(string.Join(" ", sentans));
        }
    }
}