如何在文本中添加+字符串?

我想知道如何在控制台中添加[+行]。写入线/控制台。写

例如:

string line;
    Console.WriteLine("Enter one or more lines of text (press 'gg' to exit):");
    do
    {
       Console.Write(" ");
        line = Console.ReadLine();
        if (line != "b")
            Console.WriteLine(" Sorry, you wrote **???**, which is wrong. \n Try again." +line);
       else
           Console.WriteLine("u rock");
    }
           while ( line != "gg") ;

我想在句子中间加[+行],问号在那里。