Complex sentence: If a non-free copyrighted source is being used, it is recommended to use original language and direct quotations, to clearly separate source material from original material; nevertheless, limited close paraphrasing may be acceptable under fair use in some cases.
Split into simpler sentences: If a non-free copyrighted source is being used, it is recommended to use original language and direct quotations, to clearly separate source material from original material. Nevertheless, limited close paraphrasing may be acceptable under fair use in some cases.