Creat white visual space between two lines of php code.

Hi.

Could some one please tell me how to create a couple of lines of white space between a repeated piece of code?

i.e :-

<center><?php echo do_shortcode('[???]'); ?></center>

"white space"

<center><?php echo do_shortcode('???'); ?></center>

I have tried using:-

"pre"

Which gives me exactly the space I wish to have, but it visually enlongates all that goes below it!!!!!

Thanking you in advance.

Regards

John