Class 4 General Science Notes for Punjab Board. A Complete Key\Guide Book in PDF Format for 4th class (IV) / Primary Level. These Key Book, Guide & Handwritten Notes with solved exercises are as per latest syllabus prescribed by Punjab Curriculum and Textbook Board (PCTB), Lahore. All relevant students studying in any school (government or private) in any district of Punjab Province can utilize these 4 Class notes, guides, or key books.