procedure TForm1.Button1Click(Sender: TObject);
var
T: TDateTime;
S: string;
begin
T := Now;
S := '';
S := S + '当前时间为:' + DateTimeToStr(T) + #13#10;
S := S + '减去一秒为:' + DateTimeToStr(IncMinute(T, -1)) + #13#10;
S := S + '减去一分为:' + DateTimeToStr(IncHour(T, -1)) + #13#10;
ShowMessage(S);
end;