This first paragraph has the "page-break-after" CSS2 property defined. Thus the next paragraph starts on the subpage 2, not directly after this paragraph, although the next one would fit easily on subpage 1.

This is just a normal paragraph without any forced page break definitions in CSS. The previous paragraph with the "page-break-after" CSS2 property causes this one to start here at the beginning of the subpage 2.

This paragraph starts here at the beginning of the subpage 3, because this has the "page-break-before" CSS2 property defined.