All my major textbooks in University now  comes in PDF. Studying online with the PDF documents has been extremely difficult especially with book with over 200 pages. I cant just contain it....its been so daunting trying to look for previous statement that was read on separate pages. I was thought it wise for Acrobat if it would enable such function, enabling user to colour mark texts on the document for easy referencing. Its  eally of no use printing out papers at this age. Thanks