You can use { } or (* *) or // [Delphi 2.x+] to comment out code in Delphi. But, if you have a large amount of code that you want to comment out, none of the above operators may help, depending on whether you have already used those operators in your code. Here's a definitive way to comment out code:
{$IFDEF False}
// your commented code goes hereAdvertisement

{$ENDIF}