using System;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        var list = "--fontSize 70"

                .Split("--", StringSplitOptions.RemoveEmptyEntries)

                .Select(x => $"--{x.Trim()}")

                .ToArray();

​

        Console.WriteLine(string.Join("\r\n", list));

    }

}