我想写一个从键盘按数字键1---7，触发PC喇叭发声的小程序，但是问题来了，每次运行程序只能按一次键盘，然后就没反应了，这是为什么？
源码如下：
unit Sound;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, jpeg, ExtCtrls;
type
TForm1 = class(TForm)
img1: TImage;
btn1: TButton;
btn2: TButton;
btn3: TButton;
btn4: TButton;
btn5: TButton;
btn6: TButton;
btn7: TButton;
btn8: TButton;
lbl1: TLabel;
procedure sound(d: word);
procedure btn8Click(Sender: TObject);
procedure btn1Click(Sender: TObject);
procedure btn2Click(Sender: TObject);
procedure btn3Click(Sender: TObject);
procedure btn4Click(Sender: TObject);
procedure btn5Click(Sender: TObject);
procedure btn6Click(Sender: TObject);
procedure btn7Click(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure FormKeyPress(Sender: TObject; var Key: Char);
private
FInputString: string;
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.sound(d: word);
begin
Windows.Beep(d, 100);
end;
procedure TForm1.btn8Click(Sender: TObject);
begin
Form1.Close;
end;
procedure TForm1.btn1Click(Sender: TObject);
begin
sound(100);
end;
procedure TForm1.btn2Click(Sender: TObject);
begin
sound(200);
end;
procedure TForm1.btn3Click(Sender: TObject);
begin
sound(300);
end;
procedure TForm1.btn4Click(Sender: TObject);
begin
sound(400);
end;
procedure TForm1.btn5Click(Sender: TObject);
begin
sound(500);
end;
procedure TForm1.btn6Click(Sender: TObject);
begin
sound(600);
end;
procedure TForm1.btn7Click(Sender: TObject);
begin
sound(700);
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
KeyPreview := true; //可以接收键盘操作
FInputString := '';
end;
procedure TForm1.FormKeyPress(Sender: TObject; var Key: Char);
begin
if integer(Key) >= 32 then
FInputString := FInputString + Key;
if FInputString = '1' then
btn1.Click;
if FInputString = '2' then
btn2.Click;
if FInputString = '3' then
btn3.Click;
if FInputString = '4' then
btn4.Click;
if FInputString = '5' then
btn5.Click;
if FInputString = '6' then
btn6.Click;
if FInputString = '7' then
btn7.Click;
if FInputString = '8' then
btn8.Click;
end;
end.

低级错误。你先学会debug，然后一切迎刃而解。