public string Method(int h, int m)
{
    string result = "";

    var hour = Converter(h);
    var minutes = Converter(m);
    var s = m > 1 ? "s" : "";

    if (m == 0)
    {
        return result = $"{hour} {minutes}";
    }

    if (minutes == "half" || minutes == "quarter")
    {
        switch (m)
        {
            case <= 30:
                result = $"{minutes} past {hour}";
                break;
            default:
                hour = Converter(h + 1);
                result = $"{minutes} to {hour}";
                break;

        }
    }
    else
    {
        switch (m)
        {
            case <= 30:
                result = $"{minutes} minute{s} past {hour}";
                break;
            default:
                hour = Converter(h + 1);
                result = $"{minutes} minute{s} to {hour}";
                break;

        }

    }

    return result;
}

public string Converter(int number)
{
    string result = "";
    string[] words = new string[] { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen", "twenty" };
    string[] fractions = new string[] { "o' clock", "quarter", "half" };

    switch (number)
    {
        case 0:
            result = fractions[0];
            return result;
        case 15:
        case 45:
            result = fractions[1];
            return result;
        case 30:
            result = fractions[2];
            return result;
        case <= 20: // hours
            result = words[number];
            return result;
        default:
            var wholeNumber = "";
            var unitNumber = 0;

            // for minutes lower then 30
            if (number < 30)
            {
                wholeNumber = number.ToString();
                unitNumber = int.Parse(wholeNumber.Substring(1, 1));
                result = $"{words[20]} {words[unitNumber]}";
                return result;
            }

            // for minutes past 30
            var sum = 60 - number;

            if (sum <= 20)
            {
                result = words[sum];
                return result;
            }
            else if (sum < 30)
            {
                wholeNumber = sum.ToString();
                unitNumber = int.Parse(wholeNumber.Substring(1, 1));
                result = $"{words[20]} {words[unitNumber]}";

            }

            return result;
    }

}