using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

public partial class Ex2_5 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        if (!ckb1.Checked && !ckb2.Checked && !ckb3.Checked && !ckb4.Checked)
            Response.Write("<script>alert('请选择答案！')</script>");
        else
        {
            if (ckb1.Checked && ckb2.Checked && ckb3.Checked)
                Response.Write("<script>alert('回答正确')</script>");
            else
                Response.Write("<script>alert('错误，正确答案为ABC')</script>");
        }
    }
}
