从xml检索数据(格式错误？)c#

using System;
using System.Xml;

public class XmlDataRetrieval
{
    public static void Main()
    {
        // 加载XML文件
        XmlDocument xmlDoc = new XmlDocument();
        xmlDoc.Load("data.xml");

        // 检索数据
        XmlNodeList nodeList = xmlDoc.SelectNodes("//book");
        foreach (XmlNode node in nodeList)
        {
            string title = node.SelectSingleNode("title").InnerText;
            string author = node.SelectSingleNode("author").InnerText;
            string price = node.SelectSingleNode("price").InnerText;

            Console.WriteLine("Title: " + title);
            Console.WriteLine("Author: " + author);
            Console.WriteLine("Price: " + price);
            Console.WriteLine();
        }
    }
}