我是个初学者，看了段读取文件的代码，不太懂，请大神指点，下面的源代码有两个地方有问题
                        static void GetData()
        {
            StreamReader reader = new StreamReader(Environment.CurrentDirectory + "//观测值表.txt", Encoding.UTF8);
            
            string now_line;
            while(true)
            {
                now_line = reader.ReadLine();
                if (now_line != null)
                {
                    if (now_line[0] == '控')
                    {
                        char[] sep = { '(', ',', ')', '：', ':' };//请问这里表示什么意思
                        string[] data = now_line.Split(sep);//还有这里表示什么意思
                        
                        int num = (data.Length - 2) / 4;
                        for (int i = 0; i < num; i++)
                        {
                            Point nx = new Point();
                            nx.Id = int.Parse(data[1 + 4 * i]);
                            nx.Type = Point.PointTypes.起算点;
                            nx.X = double.Parse(data[3 + 4 * i]);
                            nx.Y = double.Parse(data[4 + 4 * i]);
                            nx.X0 = nx.X;
                            nx.Y0 = nx.Y;

                            KnownPoints.Add(nx);
                            StartPoints.Add(nx);
                            AllPoint.Add(nx);

                        }
                        
                        break;
                    }
                }
            }