Why is it 'preciso de livros' and not 'preciso dos livros'?
I think that would be more specific, meaning 'need the books in English'.
Is there any rule to the verbs that must have d...(desta, daquele etc) after them? I know gosta must have d..., and pensa must have n.... but is there anyway to work out which ones must have it and which do not need it
unfortunately not =( but you can try "prepositional verbs" on Google and try to find a list of some of them =)