請幫解讀一正規表示法 "((\w+)[\s.])+"
這是一段在C#內的表示法
期望各位大大幫忙

比較不了解的是怎麼有這麼多種括號QQ

以下是原始代碼(中文標註的是我寫的,但是不知道正確不正確)

using System;
using System.Text.RegularExpressions;

public class Example
{
    public static void Main()
    {
        string input = "Yes. This dog is very friendly.";
        string pattern = @"((\w+)[\s.])+";  //      \w    數字 字母 底線  \s  空白字元
                                            //        +   一個或多個        . 含空白鍵及且其後有字元(換行除外)
        foreach (Match match in Regex.Matches(input, pattern))
        {
            Console.WriteLine("Match: {0}", match.Value);
            for (int groupCtr = 0; groupCtr < match.Groups.Count; groupCtr++)
            {
                Group group = match.Groups[groupCtr];
                Console.WriteLine("   Group {0}: {1}", groupCtr, group.Value);
                for (int captureCtr = 0; captureCtr < group.Captures.Count; captureCtr++)
                    Console.WriteLine("      Capture {0}: {1}", captureCtr,
                                      group.Captures[captureCtr].Value);
            }
        }
    }
}
// The example displays the following output:
//       Match: Yes.
//          Group 0: Yes.
//             Capture 0: Yes.
//          Group 1: Yes.
//             Capture 0: Yes.
//          Group 2: Yes
//             Capture 0: Yes
//       Match: This dog is very friendly.
//          Group 0: This dog is very friendly.
//             Capture 0: This dog is very friendly.
//          Group 1: friendly.
//             Capture 0: This
//             Capture 1: dog
//             Capture 2: is
//             Capture 3: very
//             Capture 4: friendly.
//          Group 2: friendly
//             Capture 0: This
//             Capture 1: dog
//             Capture 2: is
//             Capture 3: very
//             Capture 4: friendly