How to add empty lines (space ) ?

Hi,
I need to separate more the paragraphs with new line.

I tried:
- the tag < / br > (without spaces) but it disappear when I save the page;
- the code &-n-b-s-p-; (without lines) but it disappear when I save the page;
- the tag < p > < /p > (without spaces) but it disappear when I save the page;
- press return but the line disappears when I save the page;
- press shift+return but the line disappears when I save the page.

I think is the theme that doesn't acept all this codes.

Canyì you please tell me how can I leave a blank line?

Thanks a lot!