//声明:QueryPerformanceCounter(  var lpPerformanceCount: TLargeInteger {获取定时器每秒的频率数; TLargeInteger = Int64}): BOOL; {返回 False 表示调用失败, 或者是硬件不支持高性能定时器}         //一个有趣的示例: 判断你的鼠标点击速度; 我的最快记录是 151 毫米var  n1,n2,n,f: Int64;  b: Boolean;procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;  Shift: TShiftState; X, Y: Integer);begin  n := 0;  b := not b;  if b then QueryPerformanceCounter(n1) else begin    QueryPerformanceCounter(n2);    n := n2 - n1;  end;  if n<>0 then  begin    QueryPerformanceFrequency(f);    n := n*1000 div f;    Text := IntToStr(n) + ' ms';  end else Text := '等待第二下...';end;