大家好，请教大家一个程序的问题

大家好，我是个新手。接触delphi几天，看书上的一个例子，做出来结果跟我想象的不一样，请大家帮忙看看。选票内容里为什么不能显示“我最喜欢的手机品牌有：”和“最近想购买的大件商品”呢？谢谢各位。。

unit Unit4_3;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, CheckLst, ComCtrls;

type
  TForm1 = class(TForm)
    Label1: TLabel;
    ListBox1: TListBox;
    Label2: TLabel;
    CheckListBox1: TCheckListBox;
    Label3: TLabel;
    ComboBox1: TComboBox;
    RichEdit1: TRichEdit;
    Label4: TLabel;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
var
   Item:integer;
begin
      RichEdit1.Lines[0]:='我最喜欢的PC机品牌有:';
      RichEdit1.Lines[1]:='';         //PC机品牌
      for Item:=0 to ListBox1.Items.Count-1 do
      if ListBox1.Selected[Item] then
         RichEdit1.Lines[1]:=RichEdit1.Lines[1]+ListBox1.Items.Strings[Item]+'  ';

      RichEdit1.Lines[3]:='我最喜欢的手机品牌有:';
      RichEdit1.Lines[4]:='';         //手机品牌
      for Item:=0 to CheckListBox1.Items.Count-1 do
      if CheckListBox1.Checked[Item] then
         RichEdit1.Lines[4]:=RichEdit1.Lines[4]+CheckListBox1.Items.Strings[Item]+'  ';

      RichEdit1.Lines[6]:='我最近想买'+ComboBox1.Text;
end;

procedure TForm1.Button2Click(Sender: TObject);
var
   Item:integer;
begin
     for Item:=0 to ListBox1.Items.Count-1 do
        ListBox1.Selected[Item]:=false;

     for Item:=0 to CheckListBox1.Items.Count-1 do
        CheckListBox1.Checked[Item]:=false;

     for Item:=0 to RichEdit1.Lines.Count-1 do
        RichEdit1.Lines[Item]:='';
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
   Close;
end;


end.