一篇文章中输入关键字，抓取出来修改，并替换

try
            {
                string s = "巴塞罗那获得了欧冠冠军，皇马很忧伤！";
                string n = "在伯纳乌球场，球迷们高呼巴塞罗那是冠军！";

                Console.WriteLine("请输入一个关键字");
                string g = Console.ReadLine();

                s = s.Replace(g, "(" + g + ")");
                n = n.Replace(g, "(" + g + ")");

                Console.WriteLine(s);
                Console.WriteLine(n);
            }
            catch (Exception)
            {

                Console.WriteLine("该关键字未查到！");
            }