Don't copy and paste large amounts of text from your own pages, and certainly don't violate copyright by copying content from elsewhere. Google has been known to ban sites that duplicate too much content or at least severely penalize their ranking in search results.
Plagiarizing doesn't work in school, and it will not work online either. Take the effort to create your own original work by doing research and posting it up through your words, not others. Dup'ed pages will be deleted from now on. If you're not willing to put up the effort to make content for the site, don't bother.